code: def C(self):
          '''
          Third vertex of triangle, Point subclass.
  
          '''
          try:
              return self._C
          except AttributeError:
              pass
          self._C = Point(0, 1)
          return self._f C(self):
          '''
          Third vertex of triangle, Point subclass.
  
          '''
          try:
              return self._C
          except AttributeError:
              pass
          self._C = Point(0, 1)
          return self._C
docs: Third vertex of triangle, Point subclass.