Add note about multiple inheritance issues in PyQt5

setup/qt5-migrate.py

@@ -22,10 +22,19 @@
 
 # QT5XX: Test touchscreen support on windows 8 in the viewer
 
-# Look for obsolete classes and functions from the list here:
+# QT5XX: Look for obsolete classes and functions from the list here:
 # http://qt-project.org/doc/qt-5/obsoleteclasses.html as these will not be
 # present in PyQt5
 
+# QT5XX: For classes that inherit both a QObject based class and
+# SearchQueryParser, PyQt5 class the SearchQueryParser __init__ method when
+# calling the QObject based classes __init__ method. The simplest fix is to
+# make SearchQueryParser the first base class instead of the second. An
+# alternative fix is to create a derived class from SearchQueryParser whose
+# __init__ method accepts any args and does nothing and inherit from that. Do
+# this porting and test the results when possible. Porting already done and
+# tested for keyboard.py
+
 # QT5XX: Delete this file after migration is completed
 
 import os, re

src/calibre/gui2/keyboard.py

@@ -163,7 +163,7 @@ def __iter__(self):
         for child in self.children:
             yield child
 
-class ConfigModel(QAbstractItemModel, SearchQueryParser):
+class ConfigModel(SearchQueryParser, QAbstractItemModel):
 
     def __init__(self, keyboard, parent=None):
         QAbstractItemModel.__init__(self, parent)
@@ -556,7 +556,7 @@ def setEditorData(self, editor, index):
     def setModelData(self, editor, model, index):
         self.closeEditor.emit(editor, self.NoHint)
         custom_keys = editor.custom_keys
-        sc = index.data(Qt.UserRole).toPyObject().data
+        sc = index.data(Qt.UserRole).data
         if custom_keys is None:
             candidates = []
             for ckey in sc['default_keys']: