code: def is_coord_subset_pbc(subset, superset, atol=1e-8, mask=None):
      
      c1 = np.array(subset, dtype=np.float64)
      c2 = np.array(superset, dtype=np.float64)
      if mask is not None:
          m = np.array(mask, dtype=np.int)
      else:
          m = np.zeros((len(subset), len(superset)), dtype=np.int)
      atol = np.zeros(3, dtype=np.float64) + atol
      return cuc.is_coord_subset_pbc(c1, c2, atol, m)
docs: Tests if all fractional coords in subset are contained in superset.
  
      Args:
          subset, superset: List of fractional coords
          atol (float or size 3 array): Tolerance for matching
          mask (boolean array): Mask of matches that are not allowed.
              i.e. if mask[1,2] == True, then subset[1] cannot be matched
              to superset[2]
  
      Returns:
          True if all of subset is in superset.