docs: def _is_exception_rule(self, element):
          """ Check for "exception rule".
  
          Address elements will be appended onto a new line on the lable except
          for when the penultimate lable line fulfils certain criteria, in which
          case the element will be concatenated onto the penultimate line. This
          method checks for those criteria.
  
          i) First and last characters of the Building Name are numeric
            (eg '1to1' or '100:1')
          ii) First and penultimate characters are numeric, last character is
            alphabetic (eg '12A')
          iii) Building Name has only one character (eg 'A')
          """
          if element[0].isdigit() and element[-1].isdigit():
              return True
          if len(element) > 1 and element[0].isdigit() and element[-2].isdigit() and element[-1].isalpha():
              return True
          if len(element) == 1 and element.isalpha():
              return True
          return False