LP accepts some unknown options [cmdliner problem]

[fblanqui]

16:47 ~/src/lambdapi (db) lambdapi check --no-col
16:51 ~/src/lambdapi (db) lambdapi check --blabla
lambdapi: unknown option `--blabla'.
Usage: lambdapi check [OPTION]... [FILE]...
Try `lambdapi check --help' or `lambdapi --help' for more information.

LP accepts prefixes of known options without complaining.