Unable to import cv2

I tested the following command in python:

import cv2

I put it in the file b.py and run python b.py. But I met with the following error:

Traceback (most recent call last):
  File "b.py", line 1, in <module>
    import cv2
  File "/home/mypath/anaconda2/lib/python2.7/site-packages/cv2/__init__.py", line 9, in <module>
    from .cv2 import *
ImportError: libXdmcp.so.6: cannot open shared object file: No such file or directory

What's wrong with this? Thank you all for helping me!