code: def nan_indices(data):
      """Finds the indices of all missing values.
  
      Parameters
      ----------
      data: numpy.ndarray
  
      Returns
      -------
      List of tuples
          Indices of all missing values in tuple format; (i, j)
      """
      return np.argwhere(np.isnan(data))
  
label_desc: Use image node_id 1 for calling a global function with example usage: nan_indices(data) and returns: np