Python:安装pygresql

Question

我正在尝试使用pip在我的计算机上安装PyGreSQL模块。它显示这样一条消息：Collecting pygresql Using cached PyGreSQL-5.0.3-cp35-cp35m-win_amd64.whl Installing collected packages: pygresql Successfully installed pygresql-5.0.3，但当我尝试导入它时，下一条消息是

>>> import pygresql
   Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    ImportError: No module named 'pygresql'
 >>> from pygresql import _pg
   Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
   ImportError: No module named 'pygresql'