doctest.py 文件源码

def truncate(self,   size=None):
        StringIO.truncate(self, size)
        if hasattr(self, "softspace"):
            del self.softspace
        if not self.buf:
            # Reset it to an empty string, to make sure it's not unicode.
            self.buf = ''

# Worst-case linear-time ellipsis matching.