我在Windows 7操作系统上运行Python 2.7

这是我运行的：

>>> import matplotlib.pyplot as plt

然后我得到这个：

Traceback (most recent call last):
  File "<pyshell#3>", line 1, in <module>
    import matplotlib.pyplot as plt
  File "C:\Python27\lib\site-packages\matplotlib\pyplot.py", line 29, in <module>
    from matplotlib.figure import Figure, figaspect
  File "C:\Python27\lib\site-packages\matplotlib\figure.py", line 36, in <module>
    from matplotlib.axes import Axes, SubplotBase, subplot_class_factory
  File "C:\Python27\lib\site-packages\matplotlib\axes.py", line 20, in <module>
    import matplotlib.dates as _  # <-registers a date unit converter
  File "C:\Python27\lib\site-packages\matplotlib\dates.py", line 119, in <module>
    from dateutil.rrule import (rrule, MO, TU, WE, TH, FR, SA, SU, YEARLY,
  File "C:\Python27\lib\site-packages\dateutil\rrule.py", line 18, in <module>
    from six import advance_iterator, integer_types
ImportError: No module named six

现在，我从这里下载了六个：https :
//pypi.python.org/pypi/six

我解压缩了它，如果我从那里打开一个名为setup.py的文件，然后尝试导入matplotlib，那么它可以工作，但是我不必每次想作图时都必须这样做吗？没有办法让它自动工作吗？