def is_fin_st(id):
    """Used in p_one_line()
       ---
       Checks if id begins with f or F or if or IF.
    """
    return ( (id[0] in {'f','F'})
             or ((len(id) > 1) and (id[0:2] == 'if' or id[0:2] == 'IF')) 
           )