'Mean of the distribution.
Parameters
arg1, arg2, arg3,... : array_like
The shape parameter(s) for the distribution (see docstring of the
instance object for more information)
loc : array_like, optional
location parameter (default=0)
scale : array_like, optional
scale parameter (default=1)
Returns
mean : float
the mean of the distribution'

def mean(self, *args, **kwds):

    kwds['moments'] = 'm'
    res = self.stats(*args, **kwds)
    if (isinstance(res, ndarray) and (res.ndim == 0)):
        return res[()]
    return res
