@Substitution(name='<STR_LIT>')<EOL><INDENT>@Appender(_doc_template)<EOL>def mean(self, *args, **kwargs):<DEDENT>
nv.validate_window_func('<STR_LIT>', args, kwargs)<EOL>return self._apply('<STR_LIT>', **kwargs)<EOL>
Exponential weighted moving average.

Parameters
----------
*args, **kwargs
    Arguments and keyword arguments to be passed into func.