code: def diff(self, n=1, axis=-1):
          
          out = super(Array, self).diff(n=n, axis=axis)
          try:
              out.x0 = self.x0 + self.dx * n
          except AttributeError:  # irregular xindex
              out.x0 = self.xindex[n]
          return out
docs: Calculate the n-th order discrete difference along given axis.
  
          The first order difference is given by ``out[n] = a[n+1] - a[n]`` along
          the given axis, higher order differences are calculated by using `diff`
          recursively.
  
          Parameters
          ----------
          n : int, optional
              The number of times values are differenced.
          axis : int, optional
              The axis along which the difference is taken, default is the
              last axis.
  
          Returns
          -------
          diff : `Series`
              The `n` order differences. The shape of the output is the same
              as the input, except along `axis` where the dimension is
              smaller by `n`.
  
          See Also
          --------
          numpy.diff
              for documentation on the underlying method