code: def contains_point(self, x, y):
          
          if x is None and y is None:
              return True
          return (y * y - (x * x * x + self._a * x + self._b)) % self._p == 0
docs: :param x: x coordinate of a point
          :param y: y coordinate of a point
          :returns: True if the point (x, y) is on the curve, False otherwise