如下代码，一直有这个错误，何解？
# -*- coding: utf-8 -*-
print u'''静夜思
床前明月光，
疑是地上霜。
举头望明月，
低头思故乡。'''
Traceback (most recent call last): File "index.py", line 7, in 低头思故乡。''' UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-2: ordinal not in range(128)
