docs: def series_expand(self, param: Symbol, about, order: int):
          """Expand the matrix expression as a truncated power series in a scalar
          parameter.
  
          Args:
              param: Expansion parameter.
              about (.Scalar): Point about which to expand.
              order: Maximum order of expansion >= 0
  
          Returns:
              tuple of length (order+1), where the entries are the expansion
              coefficients.
          """
          s = self.shape
          emats = zip(*[o.series_expand(param, about, order)
                        for o in self.matrix.ravel()])
          return tuple((Matrix(np_array(em).reshape(s)) for em in emats))