fixes for python3

pyqtgraph/widgets/ComboBox.py

 from ..Qt import QtGui, QtCore
 from ..SignalProxy import SignalProxy
-from ..ordereddict import OrderedDict
+from ..pgcollections import OrderedDict
 from ..python2_3 import asUnicode
 
 class ComboBox(QtGui.QComboBox):
@@ -189,9 +189,9 @@ class ComboBox(QtGui.QComboBox):
             texts = items
             items = dict([(x, x) for x in items])
         elif isinstance(items, dict):
-            texts = items.keys()
+            texts = list(items.keys())
         else:
-            raise TypeError("items argument must be list or dict.")
+            raise TypeError("items argument must be list or dict (got %s)." % type(items))
         
         for t in texts:
             if t in self._items:
@@ -200,7 +200,7 @@ class ComboBox(QtGui.QComboBox):
         
         for k,v in items.items():
             self._items[k] = v
-        QtGui.QComboBox.addItems(self, texts)
+        QtGui.QComboBox.addItems(self, list(texts))
         
         self.itemsChanged()
         

pyqtgraph/widgets/tests/test_combobox.py

@@ -24,7 +24,7 @@ def test_combobox():
     assert cb.value() == 5
     
     # Set list instead of dict
-    cb.setItems(items.keys())
+    cb.setItems(list(items.keys()))
     assert str(cb.currentText()) == 'b'
     
     cb.setValue('c')
@@ -40,5 +40,5 @@ if __name__ == '__main__':
     cb.show()
     cb.setItems({'': None, 'a': 1, 'b': 2, 'c': 3})
     def fn(ind):
-        print "New value:", cb.value()
+        print("New value: %s" % cb.value())
     cb.currentIndexChanged.connect(fn)
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