code: def match(elem, seq_expr):
          
          if type(seq_expr) is str:  # wild-card
              if seq_expr == '.':  # match any element
                  return True
              elif seq_expr == '\d':
                  return elem.is_numerical()
              elif seq_expr == '\D':
                  return not elem.is_numerical()
              else:  # invalid wild-card specified
                  raise LookupError('{0} is not a valid wild-card'.format(seq_expr))
          else:  # date element
              return elem == seq_expr
docs: Return True if elem (an element of elem_list) matches seq_expr, an element in self.sequence