code: def is_in_plane(self, pp, dist_tolerance):
          
          return np.abs(np.dot(self.normal_vector, pp) + self._coefficients[3]) <= dist_tolerance
docs: Determines if point pp is in the plane within the tolerance dist_tolerance
          :param pp: point to be tested
          :param dist_tolerance: tolerance on the distance to the plane within which point pp is considered in the plane
          :return: True if pp is in the plane, False otherwise