def mean(self, start=None, end=None, mask=None):
        """This calculated the average value of the time series over the given
        time range from `start` to `end`, when `mask` is truthy.

        """
        return self.distribution(start=start, end=end, mask=mask).mean()
def mean ( self , start = None , end = None , mask = None ) : return self . distribution ( start = start , end = end , mask = mask ) . mean ( )
This calculated the average value of the time series over the given
        time range from `start` to `end`, when `mask` is truthy.