code: def AC(self):
          '''
          Vertices A and C, list.
  
          '''
          try:
              return self._AC
          except AttributeError:
              pass
          self._AC = [self.A, self.C]
          return self._Af AC(self):
          '''
          Vertices A and C, list.
  
          '''
          try:
              return self._AC
          except AttributeError:
              pass
          self._AC = [self.A, self.C]
          return self._AC
docs: Vertices A and C, list.