/matplotlib/dates.py 发生的错误："Can't create weekday with n == 0"

错误

Traceback (most recent call last):
  File "demo_showcandidates.py", line , in <module>
    import skimage.io
  File "/usr/local/lib/python3.4/dist-packages/skimage/io/__init__.py", line , in <module>
    reset_plugins()
  File "/usr/local/lib/python3.4/dist-packages/skimage/io/manage_plugins.py", line , in reset_plugins
    _load_preferred_plugins()
  File "/usr/local/lib/python3.4/dist-packages/skimage/io/manage_plugins.py", line , in _load_preferred_plugins
    _set_plugin(p_type, preferred_plugins['all'])
  File "/usr/local/lib/python3.4/dist-packages/skimage/io/manage_plugins.py", line , in _set_plugin
    use_plugin(plugin, kind=plugin_type)
  File "/usr/local/lib/python3.4/dist-packages/skimage/io/manage_plugins.py", line , in use_plugin
    _load(name)
  File "/usr/local/lib/python3.4/dist-packages/skimage/io/manage_plugins.py", line , in _load
    fromlist=[modname])
  File "/usr/local/lib/python3.4/dist-packages/skimage/io/_plugins/matplotlib_plugin.py", line , in <module>
    import matplotlib.pyplot as plt
  File "/usr/local/lib/python3.4/dist-packages/matplotlib/pyplot.py", line , in <module>
    from matplotlib.figure import Figure, figaspect
  File "/usr/local/lib/python3.4/dist-packages/matplotlib/figure.py", line , in <module>
    from matplotlib.axes import Axes, SubplotBase, subplot_class_factory
  File "/usr/local/lib/python3.4/dist-packages/matplotlib/axes/__init__.py", line , in <module>
    from ._subplots import *
  File "/usr/local/lib/python3.4/dist-packages/matplotlib/axes/_subplots.py", line , in <module>
    from matplotlib.axes._axes import Axes
  File "/usr/local/lib/python3.4/dist-packages/matplotlib/axes/_axes.py", line , in <module>
    import matplotlib.dates as _  # <-registers a date unit converter
  File "/usr/local/lib/python3.4/dist-packages/matplotlib/dates.py", line , in <module>
    from dateutil.rrule import (rrule, MO, TU, WE, TH, FR, SA, SU, YEARLY,
  File "/usr/local/lib/python3.4/dist-packages/dateutil/rrule.py", line 
    raise ValueError, "Can't create weekday with n == 0"
                    ^
SyntaxError: invalid syntax
           

解决

输入下面命令

sudo pip3 install --upgrade python-util