Is it possible to specify a transformer and a post lexer?

[ThatXliner]

Hi! I want to ask if

grammar = lark.Lark(
    here.joinpath("grammar.lark").read_text(),
    postlex=Indenter(),
    parser="lalr",
    maybe_placeholders=True,
    transformer=MainTransformer(),
)

is possible. I've actually tried and I've gotten this error:

Traceback (most recent call last):
  File "/Users/bryanhu/.pyenv/versions/3.6.13/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/Users/bryanhu/.pyenv/versions/3.6.13/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/Users/bryanhu/projects/langs/modcfg/modcfg/__main__.py", line 16, in <module>
    tree = parse.grammar.parse(DOC)
  File "/Users/bryanhu/projects/langs/modcfg/.venv/lib/python3.6/site-packages/lark/lark.py", line 517, in parse
    return self.parser.parse(text, start=start)
  File "/Users/bryanhu/projects/langs/modcfg/.venv/lib/python3.6/site-packages/lark/parser_frontends.py", line 115, in parse
    return self.parser.parse(lexer_thread, start)
  File "/Users/bryanhu/projects/langs/modcfg/.venv/lib/python3.6/site-packages/lark/parsers/lalr_parser.py", line 36, in parse
    return self.parser.parse(*args)
  File "/Users/bryanhu/projects/langs/modcfg/.venv/lib/python3.6/site-packages/lark/parsers/lalr_parser.py", line 136, in parse
    return self.parse_from_state(parser_state)
  File "/Users/bryanhu/projects/langs/modcfg/.venv/lib/python3.6/site-packages/lark/parsers/lalr_parser.py", line 142, in parse_from_state
    for token in state.lexer.lex(state):
  File "/Users/bryanhu/projects/langs/modcfg/.venv/lib/python3.6/site-packages/lark/indenter.py", line 37, in _process
    for token in stream:
  File "/Users/bryanhu/projects/langs/modcfg/.venv/lib/python3.6/site-packages/lark/lexer.py", line 446, in lex
    yield lexer.next_token(lexer_state, parser_state)
  File "/Users/bryanhu/projects/langs/modcfg/.venv/lib/python3.6/site-packages/lark/lexer.py", line 387, in next_token
    raise LexError("Callbacks must return a token (returned %r)" % t)
lark.exceptions.LexError: Callbacks must return a token (returned 'test')

A little help?

[MegaIng]

This is the same as #818, and has nothing to do with the Postlexer.