def METHOD_NAME(self):
    arena = test_lib.MakeArena('<lexer_test.py>')
    _, lx = test_lib.InitLexer('()', arena)
    t = lx.Read(lex_mode_e.ShCommand)
    print(t)
    self.assertEqual(Id.Op_LParen, t.id)
    t = lx.Read(lex_mode_e.ShCommand)
    print(t)
    self.assertEqual(Id.Op_RParen, t.id)
    # Go back
    lx.MaybeUnreadOne()
    # Push Hint
    lx.PushHint(Id.Op_RParen, Id.Right_CasePat)
    # Now we see it again another a Id
    t = lx.Read(lex_mode_e.ShCommand)
    print(t)
    self.assertEqual(Id.Right_CasePat, t.id)