code: def assert_is_point(point, visible=None, size=None, n_point=None):
      """Checks if points satisfy the format.
  
      This function checks if given points satisfy the format and
      raises an :class:`AssertionError` when the points violate the convention.
  
      Args:
          point (~numpy.ndarray): Points to be checked.
          visible (~numpy.ndarray): Visibility of the points.
              If this is :obj:`None`, all points are regarded as visible.
          size (tuple of ints): The size of an image.
              If this argument is specified,
              the coordinates of visible points are checked to be
              within the image.
          n_point (int): If specified, the number of points in each object is
              expected to be :obj:`n_point`.
      """
  
      for i, pnt in enumerate(point):
          assert isinstance(
              pnt, np.ndarray
          ), "pnt must be a numpy.ndarray."
          assert (
              pnt.dtype == np.float32
          ), "The type of pnt must be numpy.float32."
          assert pnt.shape[1:] == (
              2,
          ), "The shape of pnt must be (*, 2)."
          if n_point is not None:
              assert (
                  pnt.shape[0] == n_point
              ), "The number of points should always be n_point"
  
          if visible is not None:
              assert len(point) == len(
                  visible
              ), "The length of point and visible should be the same."
              vsble = visible[i]
              assert isinstance(
                  vsble, np.ndarray
              ), "pnt should be a numpy.ndarray."
              assert (
                  vsble.dtype == np.bool
              ), "The type of visible must be numpy.bool."
              assert (
                  vsble.ndim == 1
              ), "The dimensionality of a visible must be one."
              assert vsble.shape[0] == pnt.shape[0], (
                  "The size of the first axis should be the same for "
                  "corresponding pnt and vsble."
              )
              visible_pnt = pnt[vsble]
          else:
              visible_pnt = pnt
  
          if size is not None:
              assert (visible_pnt >= 0).all() and (
                  visible_pnt <= size
              ).all(), (
                  "The coordinates of visible points "
                  "should not exceed the size of image."
              )
  
label_desc: Use image node_id 1 for calling a global function with example usage: assert_is_point(point, visible, size, n_point) without return types