Exceptions in OrderedDict when using python 2.6

[tiagocoutinho]

Hello,

I am using official pyqtgraph 0.9.7 in a debian 6 64bits with Qt 4.6 and python 2.6

When I run some examples I get multiple exceptions when trying to delete an item from an ordereddict.
The bug can be reproduced easily by running the example: MultiPlotSpeedTest.py
(exception trace in attachment
Because I am using python 2.6, pyqtgraph uses the internal implementation of ordereddict which seems to be buggy.

I propose the following fix in pgcollections.py:

try:
    from collections import OrderedDict
except ImportError:
    # fallback: try to use the ordereddict backport when using python 2.6
    try:
        from ordereddict import OrderedDict
    except ImportError:
        # backport not installed: use local OrderedDict
        class OrderedDict():
            # local impl

[tiagocoutinho (coutinhotiago)]

The patch is proposed by me and (Kif) Jerome Kieffer who already proposed something similar to vispy (issue #68 on github)

[lcampagn (luke-campagnola)]

Thank you!
Your patch will appear in 0.9.8.
FYI, there is now a github repository for pyqtgraph. If all goes well through the 0.9.8 release, we will officially switch over and shut down the launchpad repository.