Hi, why do i get KeyError: 'Patch' ? thanks

xiliu@master:/tmp/matplotlib-0.99.1.1$ python

Python 2.6 (r26:66714, Nov  3 2009, 17:33:38)

[GCC 4.4.1 20090725 (Red Hat 4.4.1-2)] on linux2

Type "help", "copyright", "credits" or "license" for more information.

>>> import matplotlib.pyplot as plt
Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

  File "/usr/lib/python2.6/site-packages/matplotlib/pyplot.py", line 6, in <module>

    from matplotlib.figure import Figure, figaspect
  File "/usr/lib/python2.6/site-packages/matplotlib/figure.py", line 18, in <module>

    from axes import Axes, SubplotBase, subplot_class_factory

  File "/usr/lib/python2.6/site-packages/matplotlib/axes.py", line 24, in <module>

    import matplotlib.spines as mspines
  File "/usr/lib/python2.6/site-packages/matplotlib/spines.py", line 17, in <module>

    class Spine(mpatches.Patch):
  File "/usr/lib/python2.6/site-packages/matplotlib/spines.py", line 39, in Spine

    @docstring.dedent_interpd
  File "/usr/lib/python2.6/site-packages/matplotlib/docstring.py", line 103, in dedent_interpd

    return interpd(dedent(func))
  File "/usr/lib/python2.6/site-packages/matplotlib/docstring.py", line 36, in __call__

    func.__doc__ = func.__doc__ and func.__doc__ % self.params

KeyError: 'Patch'
>>>