Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/skimage/viewer/qt.py

@@ -0,0 +1,44 @@
+_qt_version = None
+has_qt = True
+
+try:
+    from matplotlib.backends.qt_compat import QtGui, QtCore, QtWidgets, QT_RC_MAJOR_VERSION as _qt_version
+except ImportError:
+    try:
+        from matplotlib.backends.qt4_compat import QtGui, QtCore
+        QtWidgets = QtGui
+        _qt_version = 4
+    except ImportError:
+        # Mock objects
+        class QtGui_cls(object):
+            QMainWindow = object
+            QDialog = object
+            QWidget = object
+
+        class QtCore_cls(object):
+            class Qt(object):
+                 TopDockWidgetArea = None
+                 BottomDockWidgetArea = None
+                 LeftDockWidgetArea = None
+                 RightDockWidgetArea = None
+
+            def Signal(self, *args, **kwargs): 
+                pass
+
+        QtGui = QtWidgets = QtGui_cls()
+        QtCore = QtCore_cls()
+
+        has_qt = False
+
+if _qt_version == 5:
+    from matplotlib.backends.backend_qt5 import FigureManagerQT
+    from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg
+elif _qt_version == 4:
+    from matplotlib.backends.backend_qt4 import FigureManagerQT
+    from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg
+else:
+    FigureManagerQT = object
+    FigureCanvasQTAgg = object
+
+Qt = QtCore.Qt
+Signal = QtCore.Signal