code: def ABC(self):
          '''
          A list of the triangle's vertices, list.
  
          '''
          try:
              return self._ABC
          except AttributeError:
              pass
          self._ABC = [self.A, self.B, self.C]
          return self._ABf ABC(self):
          '''
          A list of the triangle's vertices, list.
  
          '''
          try:
              return self._ABC
          except AttributeError:
              pass
          self._ABC = [self.A, self.B, self.C]
          return self._ABC
docs: A list of the triangle's vertices, list.