code: def einsum_sequence(self, other_arrays, einsum_string=None):
          
          if not isinstance(other_arrays, list):
              raise ValueError("other tensors must be list of "
                               "tensors or tensor input")
  
          other_arrays = [np.array(a) for a in other_arrays]
          if not einsum_string:
              lc = string.ascii_lowercase
              einsum_string = lc[:self.rank]
              other_ranks = [len(a.shape) for a in other_arrays]
              idx = self.rank - sum(other_ranks)
              for length in other_ranks:
                  einsum_string += ',' + lc[idx:idx + length]
                  idx += length
  
          einsum_args = [self] + list(other_arrays)
          return np.einsum(einsum_string, *einsum_args)
docs: Calculates the result of an einstein summation expression