Added pylint config, code improvements suggested by pylint

7 files changed, 657 insertions, 59 deletions

diff --git a/.pylintrc b/.pylintrc
new file mode 100644
index 0000000..f56d259
--- /dev/null
+++ b/.pylintrc
@@ -0,0 +1,570 @@
+[MASTER]
+
+# A comma-separated list of package or module names from where C extensions may
+# be loaded. Extensions are loading into the active Python interpreter and may
+# run arbitrary code.
+extension-pkg-allow-list=
+
+# A comma-separated list of package or module names from where C extensions may
+# be loaded. Extensions are loading into the active Python interpreter and may
+# run arbitrary code. (This is an alternative name to extension-pkg-allow-list
+# for backward compatibility.)
+extension-pkg-whitelist=
+
+# Return non-zero exit code if any of these messages/categories are detected,
+# even if score is above --fail-under value. Syntax same as enable. Messages
+# specified are enabled, while categories only check already-enabled messages.
+fail-on=
+
+# Specify a score threshold to be exceeded before program exits with error.
+fail-under=10.0
+
+# Files or directories to be skipped. They should be base names, not paths.
+ignore=CVS
+
+# Add files or directories matching the regex patterns to the ignore-list. The
+# regex matches against paths and can be in Posix or Windows format.
+ignore-paths=
+
+# Files or directories matching the regex patterns are skipped. The regex
+# matches against base names, not paths.
+ignore-patterns=
+
+# Python code to execute, usually for sys.path manipulation such as
+# pygtk.require().
+#init-hook=
+
+# Use multiple processes to speed up Pylint. Specifying 0 will auto-detect the
+# number of processors available to use.
+jobs=1
+
+# Control the amount of potential inferred values when inferring a single
+# object. This can help the performance when dealing with large functions or
+# complex, nested conditions.
+limit-inference-results=100
+
+# List of plugins (as comma separated values of python module names) to load,
+# usually to register additional checkers.
+load-plugins=
+
+# Pickle collected data for later comparisons.
+persistent=yes
+
+# Minimum Python version to use for version dependent checks. Will default to
+# the version used to run pylint.
+py-version=3.10
+
+# When enabled, pylint would attempt to guess common misconfiguration and emit
+# user-friendly hints instead of false-positive error messages.
+suggestion-mode=yes
+
+# Allow loading of arbitrary C extensions. Extensions are imported into the
+# active Python interpreter and may run arbitrary code.
+unsafe-load-any-extension=no
+
+
+[MESSAGES CONTROL]
+
+# Only show warnings with the listed confidence levels. Leave empty to show
+# all. Valid levels: HIGH, INFERENCE, INFERENCE_FAILURE, UNDEFINED.
+confidence=
+
+# Disable the message, report, category or checker with the given id(s). You
+# can either give multiple identifiers separated by comma (,) or put this
+# option multiple times (only on the command line, not in the configuration
+# file where it should appear only once). You can also use "--disable=all" to
+# disable everything first and then reenable specific checks. For example, if
+# you want to run only the similarities checker, you can use "--disable=all
+# --enable=similarities". If you want to run only the classes checker, but have
+# no Warning level messages displayed, use "--disable=all --enable=classes
+# --disable=W".
+disable=raw-checker-failed,
+        bad-inline-option,
+        locally-disabled,
+        file-ignored,
+        suppressed-message,
+        useless-suppression,
+        deprecated-pragma,
+        use-symbolic-message-instead
+
+# Enable the message, report, category or checker with the given id(s). You can
+# either give multiple identifier separated by comma (,) or put this option
+# multiple time (only on the command line, not in the configuration file where
+# it should appear only once). See also the "--disable" option for examples.
+enable=c-extension-no-member
+
+
+[REPORTS]
+
+# Python expression which should return a score less than or equal to 10. You
+# have access to the variables 'error', 'warning', 'refactor', and 'convention'
+# which contain the number of messages in each category, as well as 'statement'
+# which is the total number of statements analyzed. This score is used by the
+# global evaluation report (RP0004).
+evaluation=10.0 - ((float(5 * error + warning + refactor + convention) / statement) * 10)
+
+# Template used to display messages. This is a python new-style format string
+# used to format the message information. See doc for all details.
+#msg-template=
+
+# Set the output format. Available formats are text, parseable, colorized, json
+# and msvs (visual studio). You can also give a reporter class, e.g.
+# mypackage.mymodule.MyReporterClass.
+output-format=text
+
+# Tells whether to display a full report or only the messages.
+reports=no
+
+# Activate the evaluation score.
+score=yes
+
+
+[REFACTORING]
+
+# Maximum number of nested blocks for function / method body
+max-nested-blocks=5
+
+# Complete name of functions that never returns. When checking for
+# inconsistent-return-statements if a never returning function is called then
+# it will be considered as an explicit return statement and no message will be
+# printed.
+never-returning-functions=sys.exit,argparse.parse_error
+
+
+[TYPECHECK]
+
+# List of decorators that produce context managers, such as
+# contextlib.contextmanager. Add to this list to register other decorators that
+# produce valid context managers.
+contextmanager-decorators=contextlib.contextmanager
+
+# List of members which are set dynamically and missed by pylint inference
+# system, and so shouldn't trigger E1101 when accessed. Python regular
+# expressions are accepted.
+generated-members=
+
+# Tells whether missing members accessed in mixin class should be ignored. A
+# class is considered mixin if its name matches the mixin-class-rgx option.
+ignore-mixin-members=yes
+
+# Tells whether to warn about missing members when the owner of the attribute
+# is inferred to be None.
+ignore-none=yes
+
+# This flag controls whether pylint should warn about no-member and similar
+# checks whenever an opaque object is returned when inferring. The inference
+# can return multiple potential results while evaluating a Python object, but
+# some branches might not be evaluated, which results in partial inference. In
+# that case, it might be useful to still emit no-member and other checks for
+# the rest of the inferred objects.
+ignore-on-opaque-inference=yes
+
+# List of class names for which member attributes should not be checked (useful
+# for classes with dynamically set attributes). This supports the use of
+# qualified names.
+ignored-classes=optparse.Values,thread._local,_thread._local
+
+# List of module names for which member attributes should not be checked
+# (useful for modules/projects where namespaces are manipulated during runtime
+# and thus existing member attributes cannot be deduced by static analysis). It
+# supports qualified module names, as well as Unix pattern matching.
+ignored-modules=
+
+# Show a hint with possible names when a member name was not found. The aspect
+# of finding the hint is based on edit distance.
+missing-member-hint=yes
+
+# The minimum edit distance a name should have in order to be considered a
+# similar match for a missing member name.
+missing-member-hint-distance=1
+
+# The total number of similar names that should be taken in consideration when
+# showing a hint for a missing member.
+missing-member-max-choices=1
+
+# Regex pattern to define which classes are considered mixins ignore-mixin-
+# members is set to 'yes'
+mixin-class-rgx=.*[Mm]ixin
+
+# List of decorators that change the signature of a decorated function.
+signature-mutators=
+
+
+[LOGGING]
+
+# The type of string formatting that logging methods do. `old` means using %
+# formatting, `new` is for `{}` formatting.
+logging-format-style=old
+
+# Logging modules to check that the string format arguments are in logging
+# function parameter format.
+logging-modules=logging
+
+
+[STRING]
+
+# This flag controls whether inconsistent-quotes generates a warning when the
+# character used as a quote delimiter is used inconsistently within a module.
+check-quote-consistency=no
+
+# This flag controls whether the implicit-str-concat should generate a warning
+# on implicit string concatenation in sequences defined over several lines.
+check-str-concat-over-line-jumps=no
+
+
+[SPELLING]
+
+# Limits count of emitted suggestions for spelling mistakes.
+max-spelling-suggestions=4
+
+# Spelling dictionary name. Available dictionaries: none. To make it work,
+# install the 'python-enchant' package.
+spelling-dict=
+
+# List of comma separated words that should be considered directives if they
+# appear and the beginning of a comment and should not be checked.
+spelling-ignore-comment-directives=fmt: on,fmt: off,noqa:,noqa,nosec,isort:skip,mypy:
+
+# List of comma separated words that should not be checked.
+spelling-ignore-words=
+
+# A path to a file that contains the private dictionary; one word per line.
+spelling-private-dict-file=
+
+# Tells whether to store unknown words to the private dictionary (see the
+# --spelling-private-dict-file option) instead of raising a message.
+spelling-store-unknown-words=no
+
+
+[BASIC]
+
+# Naming style matching correct argument names.
+argument-naming-style=camelCase
+
+# Regular expression matching correct argument names. Overrides argument-
+# naming-style.
+#argument-rgx=
+
+# Naming style matching correct attribute names.
+attr-naming-style=camelCase
+
+# Regular expression matching correct attribute names. Overrides attr-naming-
+# style.
+#attr-rgx=
+
+# Bad variable names which should always be refused, separated by a comma.
+bad-names=foo,
+          bar,
+          baz,
+          toto,
+          tutu,
+          tata
+
+# Bad variable names regexes, separated by a comma. If names match any regex,
+# they will always be refused
+bad-names-rgxs=
+
+# Naming style matching correct class attribute names.
+class-attribute-naming-style=any
+
+# Regular expression matching correct class attribute names. Overrides class-
+# attribute-naming-style.
+#class-attribute-rgx=
+
+# Naming style matching correct class constant names.
+class-const-naming-style=UPPER_CASE
+
+# Regular expression matching correct class constant names. Overrides class-
+# const-naming-style.
+#class-const-rgx=
+
+# Naming style matching correct class names.
+class-naming-style=PascalCase
+
+# Regular expression matching correct class names. Overrides class-naming-
+# style.
+#class-rgx=
+
+# Naming style matching correct constant names.
+const-naming-style=UPPER_CASE
+
+# Regular expression matching correct constant names. Overrides const-naming-
+# style.
+#const-rgx=
+
+# Minimum line length for functions/classes that require docstrings, shorter
+# ones are exempt.
+docstring-min-length=-1
+
+# Naming style matching correct function names.
+function-naming-style=camelCase
+
+# Regular expression matching correct function names. Overrides function-
+# naming-style.
+#function-rgx=
+
+# Good variable names which should always be accepted, separated by a comma.
+good-names=i,
+           j,
+           k,
+           ex,
+           Run,
+           _,
+           uut,
+           ch
+
+# Good variable names regexes, separated by a comma. If names match any regex,
+# they will always be accepted
+good-names-rgxs=
+
+# Include a hint for the correct naming format with invalid-name.
+include-naming-hint=no
+
+# Naming style matching correct inline iteration names.
+inlinevar-naming-style=any
+
+# Regular expression matching correct inline iteration names. Overrides
+# inlinevar-naming-style.
+#inlinevar-rgx=
+
+# Naming style matching correct method names.
+method-naming-style=camelCase
+
+# Regular expression matching correct method names. Overrides method-naming-
+# style.
+#method-rgx=
+
+# Naming style matching correct module names.
+module-naming-style=snake_case
+
+# Regular expression matching correct module names. Overrides module-naming-
+# style.
+#module-rgx=
+
+# Colon-delimited sets of names that determine each other's naming style when
+# the name regexes allow several styles.
+name-group=
+
+# Regular expression which should only match function or class names that do
+# not require a docstring.
+no-docstring-rgx=^_
+
+# List of decorators that produce properties, such as abc.abstractproperty. Add
+# to this list to register other decorators that produce valid properties.
+# These decorators are taken in consideration only for invalid-name.
+property-classes=abc.abstractproperty
+
+# Naming style matching correct variable names.
+variable-naming-style=camelCase
+
+# Regular expression matching correct variable names. Overrides variable-
+# naming-style.
+#variable-rgx=
+
+
+[FORMAT]
+
+# Expected format of line ending, e.g. empty (any line ending), LF or CRLF.
+expected-line-ending-format=
+
+# Regexp for a line that is allowed to be longer than the limit.
+ignore-long-lines=^\s*(# )?<?https?://\S+>?$
+
+# Number of spaces of indent required inside a hanging or continued line.
+indent-after-paren=4
+
+# String used as indentation unit. This is usually "    " (4 spaces) or "\t" (1
+# tab).
+indent-string='    '
+
+# Maximum number of characters on a single line.
+max-line-length=100
+
+# Maximum number of lines in a module.
+max-module-lines=1000
+
+# Allow the body of a class to be on the same line as the declaration if body
+# contains single statement.
+single-line-class-stmt=no
+
+# Allow the body of an if to be on the same line as the test if there is no
+# else.
+single-line-if-stmt=no
+
+
+[MISCELLANEOUS]
+
+# List of note tags to take in consideration, separated by a comma.
+notes=FIXME,
+      XXX,
+      TODO
+
+# Regular expression of note tags to take in consideration.
+#notes-rgx=
+
+
+[SIMILARITIES]
+
+# Comments are removed from the similarity computation
+ignore-comments=yes
+
+# Docstrings are removed from the similarity computation
+ignore-docstrings=yes
+
+# Imports are removed from the similarity computation
+ignore-imports=no
+
+# Signatures are removed from the similarity computation
+ignore-signatures=no
+
+# Minimum lines number of a similarity.
+min-similarity-lines=4
+
+
+[VARIABLES]
+
+# List of additional names supposed to be defined in builtins. Remember that
+# you should avoid defining new builtins when possible.
+additional-builtins=
+
+# Tells whether unused global variables should be treated as a violation.
+allow-global-unused-variables=yes
+
+# List of names allowed to shadow builtins
+allowed-redefined-builtins=
+
+# List of strings which can identify a callback function by name. A callback
+# name must start or end with one of those strings.
+callbacks=cb_,
+          _cb
+
+# A regular expression matching the name of dummy variables (i.e. expected to
+# not be used).
+dummy-variables-rgx=_+$|(_[a-zA-Z0-9_]*[a-zA-Z0-9]+?$)|dummy|^ignored_|^unused_
+
+# Argument names that match this expression will be ignored. Default to name
+# with leading underscore.
+ignored-argument-names=_.*|^ignored_|^unused_
+
+# Tells whether we should check for unused import in __init__ files.
+init-import=no
+
+# List of qualified module names which can have objects that can redefine
+# builtins.
+redefining-builtins-modules=six.moves,past.builtins,future.builtins,builtins,io
+
+
+[DESIGN]
+
+# List of regular expressions of class ancestor names to ignore when counting
+# public methods (see R0903)
+exclude-too-few-public-methods=
+
+# List of qualified class names to ignore when counting class parents (see
+# R0901)
+ignored-parents=
+
+# Maximum number of arguments for function / method.
+max-args=5
+
+# Maximum number of attributes for a class (see R0902).
+max-attributes=7
+
+# Maximum number of boolean expressions in an if statement (see R0916).
+max-bool-expr=5
+
+# Maximum number of branch for function / method body.
+max-branches=12
+
+# Maximum number of locals for function / method body.
+max-locals=15
+
+# Maximum number of parents for a class (see R0901).
+max-parents=7
+
+# Maximum number of public methods for a class (see R0904).
+max-public-methods=20
+
+# Maximum number of return / yield for function / method body.
+max-returns=6
+
+# Maximum number of statements in function / method body.
+max-statements=50
+
+# Minimum number of public methods for a class (see R0903).
+min-public-methods=2
+
+
+[CLASSES]
+
+# Warn about protected attribute access inside special methods
+check-protected-access-in-special-methods=no
+
+# List of method names used to declare (i.e. assign) instance attributes.
+defining-attr-methods=__init__,
+                      __new__,
+                      setUp,
+                      __post_init__
+
+# List of member names, which should be excluded from the protected access
+# warning.
+exclude-protected=_asdict,
+                  _fields,
+                  _replace,
+                  _source,
+                  _make
+
+# List of valid names for the first argument in a class method.
+valid-classmethod-first-arg=cls
+
+# List of valid names for the first argument in a metaclass class method.
+valid-metaclass-classmethod-first-arg=cls
+
+
+[IMPORTS]
+
+# List of modules that can be imported at any level, not just the top level
+# one.
+allow-any-import-level=
+
+# Allow wildcard imports from modules that define __all__.
+allow-wildcard-with-all=no
+
+# Analyse import fallback blocks. This can be used to support both Python 2 and
+# 3 compatible code, which means that the block might have code that exists
+# only in one or another interpreter, leading to false positives when analysed.
+analyse-fallback-blocks=no
+
+# Deprecated modules which should not be used, separated by a comma.
+deprecated-modules=
+
+# Output a graph (.gv or any supported image format) of external dependencies
+# to the given file (report RP0402 must not be disabled).
+ext-import-graph=
+
+# Output a graph (.gv or any supported image format) of all (i.e. internal and
+# external) dependencies to the given file (report RP0402 must not be
+# disabled).
+import-graph=
+
+# Output a graph (.gv or any supported image format) of internal dependencies
+# to the given file (report RP0402 must not be disabled).
+int-import-graph=
+
+# Force import order to recognize a module as part of the standard
+# compatibility libraries.
+known-standard-library=
+
+# Force import order to recognize a module as part of a third party library.
+known-third-party=enchant
+
+# Couples of modules and preferred modules, separated by a comma.
+preferred-modules=
+
+
+[EXCEPTIONS]
+
+# Exceptions that will emit a warning when being caught. Defaults to
+# "BaseException, Exception".
+overgeneral-exceptions=BaseException,
+                       Exception
diff --git a/lab_control/__init__.py b/lab_control/__init__.py
index b8c59c6..e69de29 100644
--- a/lab_control/__init__.py
+++ b/lab_control/__init__.py
@@ -1,3 +0,0 @@
-#from os.path import dirname, abspath
-
-#ROOT_DIR = dirname(abspath(__file__))
diff --git a/lab_control/function_generator.py b/lab_control/function_generator.py
index be522d9..a403784 100644
--- a/lab_control/function_generator.py
+++ b/lab_control/function_generator.py
@@ -1,23 +1,24 @@
-class FunctionGenerator:
-    SINE       = 0
-    SQUARE     = 1
-    TRIANGULAR = 3
+""" Interface definition for function generator devices. """
 
+class FunctionGenerator:
+    """
+    This interface specifies the common API for all
+    supported function generator devices.
+    """
     def __init__(self):
-        raise Exception("This class should not be instantiated directly, please extend it instead")
+        pass
 
     def setOn(self, channel: int) -> None:
-        pass
+        """ Enable channel. """
 
     def setOff(self, channel: int) -> None:
-        pass
+        """ Disable channel. """
 
     def setFrequency(self, channel: int, frequency: float) -> None:
-        pass
+        """ Set channel output frequency. """
 
     def setAmplitude(self, channel: int, amplitude: float) -> None:
-        pass
+        """ Set channel output amplitude. """
 
     def setFunction(self, channel: int, function: int) -> None:
-        pass
-
+        """ Set channel output waveform. """
diff --git a/lab_control/jds6600.py b/lab_control/jds6600.py
index 006a041..5ada6cf 100644
--- a/lab_control/jds6600.py
+++ b/lab_control/jds6600.py
@@ -1,25 +1,44 @@
+"""
+Implements partial support for Joy-IT JDS6600 function generator.
+"""
+
 import serial
-import re
 
 from lab_control.function_generator import FunctionGenerator
 
+def _checkChannel(channel: int):
+    assert channel in JDS6600.AVAILABLE_CHANNELS, f"JDS6600: Invalid channel {channel}"
+
+def _checkArg(arg: float, lowerBound: float, upperBound: float):
+    valid = arg is not None
+    if valid:
+        valid &= arg >= lowerBound
+        valid &= arg <= upperBound
+    assert valid, f"JDS6600: Invalid argument {arg}"
+
 class JDS6600(FunctionGenerator):
+    """
+    Instances of this class bind to the JDS6600 serial port
+    and offer an API to control the device.
+    """
     AVAILABLE_CHANNELS = [1, 2]
+    SINE       = 0
+    SQUARE     = 1
+    TRIANGULAR = 3
 
     def __init__(self, portName):
+        super().__init__()
         self._port = serial.Serial(portName)
         self._port.baudrate = 115200
         self._port.bytesize = serial.EIGHTBITS
         self._port.stopbits = serial.STOPBITS_ONE
         self._port.parity = serial.PARITY_NONE
 
-    def _sendRequest(self, opcode: str, args: str="") -> str:
-        request = f":{opcode}={args}.\r\n"
-        self._port.write(request.encode())
-        responseRaw = self._port.readline()
-        return responseRaw.decode().strip()
-
     def closePort(self) -> None:
+        """
+        Close the serial port. Instances of this class
+        are no longer usable after this is called.
+        """
         self._port.close()
 
     def _queryOnOff(self) -> list[str, str]:
@@ -27,39 +46,45 @@ class JDS6600(FunctionGenerator):
         response = self._sendRequest("r20")
         return [response[5], response[7]]
 
+    def _sendRequest(self, opcode: str, args: str="") -> str:
+        request = f":{opcode}={args}.\r\n"
+        self._port.write(request.encode())
+        responseRaw = self._port.readline()
+        return responseRaw.decode().strip()
+
     def setOn(self, channel: int) -> None:
-        assert channel in JDS6600.AVAILABLE_CHANNELS, f"JDS6600: Invalid channel {channel}"
+        _checkChannel(channel)
 
         state = self._queryOnOff()
         state[channel - 1] = "1"
-        response = self._sendRequest("w20", f"{state[0]},{state[1]}")
+        self._sendRequest("w20", f"{state[0]},{state[1]}")
 
     def setOff(self, channel: int) -> None:
-        assert channel in JDS6600.AVAILABLE_CHANNELS, f"JDS6600: Invalid channel {channel}"
+        _checkChannel(channel)
 
         state = self._queryOnOff()
         state[channel - 1] = "0"
-        response = self._sendRequest("w20", f"{state[0]},{state[1]}")
+        self._sendRequest("w20", f"{state[0]},{state[1]}")
 
     def setFrequency(self, channel: int, frequency: float) -> None:
-        assert channel in JDS6600.AVAILABLE_CHANNELS, f"JDS6600: Invalid channel {channel}"
-        assert frequency is not None and frequency >= 0.0 and frequency <= 60e6, f"JDS6600: Invalid frequency {frequency}"
+        _checkChannel(channel)
+        _checkArg(frequency, 0.0, 60e6)
 
         opcode = f"w{23 + channel - 1}"
         arg = int(frequency * 100.0)
-        response = self._sendRequest(opcode, str(arg))
+        self._sendRequest(opcode, str(arg))
 
     def setAmplitude(self, channel: int, amplitude: float) -> None:
-        assert channel in JDS6600.AVAILABLE_CHANNELS, f"JDS6600: Invalid channel {channel}"
-        assert amplitude is not None and amplitude >= 0.0 and amplitude <= 20.0, f"JDS6600: Invalid amplitude {amplitude}"
+        _checkChannel(channel)
+        _checkArg(amplitude, 0.0, 20.0)
 
         opcode = f"w{25 + channel - 1}"
         arg = int(amplitude * 1000.0)
-        response = self._sendRequest(opcode, str(arg))
+        self._sendRequest(opcode, str(arg))
 
     def setFunction(self, channel: int, function: int) -> None:
-        assert channel in JDS6600.AVAILABLE_CHANNELS, f"JDS6600: Invalid channel {channel}"
-        assert function is not None and function >= 0 and function <= 16, f"JDS6600: Invalid function code {function}"
+        _checkChannel(channel)
+        _checkArg(function, 0, 16)
 
         opcode = f"w{21 + channel - 1}"
-        response = self._sendRequest(opcode, str(function))
+        self._sendRequest(opcode, str(function))
diff --git a/lab_control/oscilloscope.py b/lab_control/oscilloscope.py
index 9f2d02c..e4b5a89 100644
--- a/lab_control/oscilloscope.py
+++ b/lab_control/oscilloscope.py
@@ -1,17 +1,21 @@
+""" Interface definition for oscilloscope devices. """
+
 class Oscilloscope:
+    """
+    This interface specifies the common API for all
+    supported oscilloscope devices.
+    """
     def __init__(self):
-        raise Exception("This class should not be instantiated directly, please extend it instead")
+        pass
 
     def measureAmplitude(self, channel: int) -> float:
-        pass
+        """ Return amplitude measurement on specific channel. """
 
     def measurePeakToPeak(self, channel: int) -> float:
-        pass
+        """ Return peak-to-peak measurement on specific channel. """
 
     def measureRMS(self, channel: int) -> float:
-        pass
+        """ Return RMS measurement on specific channel. """
 
     def measureFrequency(self, channel: int) -> float:
-        pass
-
-
+        """ Return frequency measurement on specific channel. """
diff --git a/lab_control/sds1000xe.py b/lab_control/sds1000xe.py
index 859b1bf..67fc29b 100644
--- a/lab_control/sds1000xe.py
+++ b/lab_control/sds1000xe.py
@@ -1,31 +1,44 @@
+"""
+Implements partial support for Siglent SDS1000X-E series oscilloscopes.
+"""
+
 import socket
 import re
 from lab_control.oscilloscope import Oscilloscope
 
+def _checkChannel(channel):
+    assert channel in SDS1000XE.AVAILABLE_CHANNELS, "SDS1000X-E: Invalid channel {channel}"
+
 class SDS1000XE(Oscilloscope):
+    """
+    Instances of this class connect to the SDS1000X-E IP
+    and port and offer an API to control the device.
+    """
     PORT = 5025
     TIMEOUT = 1.0
     AVAILABLE_CHANNELS = range(1, 5)
 
     def __init__(self, address):
+        super().__init__()
         self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         self._socket.connect((address, SDS1000XE.PORT))
         self._socket.settimeout(SDS1000XE.TIMEOUT)
 
-    def _measure(self, channel: int, code: str) -> float:
-        assert channel in SDS1000XE.AVAILABLE_CHANNELS, "SDS1000X-E: Invalid channel {channel}"
 
+    def _measure(self, channel: int, code: str) -> float:
+        _checkChannel(channel)
+        pattern = r"C(?P<responseChannel>\d):PAVA .+,(?P<rawMeasurement>[\d.E+-]+)\w+"
         query = f"C{channel}:PAVA? {code}\r\n"
         self._socket.sendall(query.encode())
 
         try:
             # TODO add code to regex
             response = self._socket.recv(4096).decode()
-            m = re.search(r"C(?P<responseChannel>\d):PAVA .+,(?P<rawMeasurement>[\d.E+-]+)\w+", response)
-            measurement = float(m.group("rawMeasurement"))
-        except TimeoutError as e:
+            matches = re.search(pattern, response)
+            measurement = float(matches.group("rawMeasurement"))
+        except TimeoutError:
             measurement = None
-        
+
         return measurement
 
     def measureAmplitude(self, channel: int) -> float:
@@ -39,4 +52,3 @@ class SDS1000XE(Oscilloscope):
 
     def measureFrequency(self, channel: int) -> float:
         return self._measure(channel, "FREQ")
-
diff --git a/lab_control/test/interfaces_test.py b/lab_control/test/interfaces_test.py
deleted file mode 100644
index bf9006b..0000000
--- a/lab_control/test/interfaces_test.py
+++ /dev/null
@@ -1,11 +0,0 @@
-import pytest
-from lab_control.oscilloscope import Oscilloscope
-from lab_control.function_generator import FunctionGenerator
-
-def test_oscilloscopeInterface():
-    with pytest.raises(Exception):
-        uut = Oscilloscope()
-
-def test_functionGeneratorInterface():
-    with pytest.raises(Exception):
-        uut = FunctionGenerator()