code: def AB(self):
          '''
          A list containing Points A and B.
          '''
          try:
              return self._AB
          except AttributeError:
              pass
          self._AB = [self.A, self.B]
          return self._Af AB(self):
          '''
          A list containing Points A and B.
          '''
          try:
              return self._AB
          except AttributeError:
              pass
          self._AB = [self.A, self.B]
          return self._AB
docs: A list containing Points A and B.