try RTD fix: try on_rtd check to redefine QWidget

docs/conf.py

@@ -13,19 +13,15 @@
 if on_rtd:
     html_theme = 'default'
 
-    sys.path.insert(0, os.path.abspath('.'))
-
     from unittest.mock import MagicMock
-    import mock_qtwidgets
 
     class Mock(MagicMock):
         @classmethod
         def __getattr__(cls, name):
             return MagicMock()
 
-    MOCK_MODULES = ['PyQt5', 'PyQt5.QtCore', 'PyQt5.QtGui']
+    MOCK_MODULES = ['PyQt5', 'PyQt5.QtWidgets', 'PyQt5.QtCore', 'PyQt5.QtGui']
     sys.modules.update((mod_name, Mock()) for mod_name in MOCK_MODULES)
-    sys.modules.update((('PyQt5.QtWidgets', mock_qtwidgets),))
 
 else:
     html_theme = 'sphinx_rtd_theme'

msl/qt/logger.py

@@ -1,15 +1,20 @@
 """
 A :class:`QWidget` to display :mod:`logging` messages.
 """
+import os
 import logging
 
 from PyQt5 import QtWidgets, QtGui, Qt
 
+on_rtd = os.environ.get('READTHEDOCS') == 'True'
+if on_rtd:
+    QtWidgets = object
+
 from msl.qt import prompt
 from msl.qt.io import get_icon
 
 
-class Logger(logging.Handler):#, QtWidgets.QWidget):
+class Logger(logging.Handler, QtWidgets.QWidget):
 
     def __init__(self,
                  level=logging.INFO,