Parser in e2e_asr_transducer is missing a return statment

In the code: https://github.com/espnet/espnet/blob/master/espnet/nets/pytorch_backend/e2e_asr_transducer.py

You’re not returning parser in add_arguments. This throws an error when attempting to call E2E.build()

[thethiny]

Thank you for the PR that fixes the issue. I read your explanation and came to understanding of your point. What you’re doing is passing a parser object by reference to the add_argument function, which is working well for you. However, in your code /path/to/utils/fill_missing_args.py you’re assuming that parser is returned, since you’re calling parse_known_args() on the execution of the function, therefore failing in this case. Another solution can be introduced which is to change the line default_args, _ = add_arguments(argparse.ArgumentParser()).parse_known_args() into separate lines as so:

parser = argparse.ArgumentParser()
add_arguments(parser)
default_args, _ = parser.parse_known_args()

Regards,

[ahmedalbahnasawy]

Thanks for taking the time to review my issue. The issue arises when trying to import E2E asr_transducer, then using the command E2E.build(). The error occurs when the line default_args, _ = add_arguments(argparse.ArgumentParser()).parse_known_args() is executed in the file (...)/espnet/utils/fill_missing_args.py. Using the available train and eval files will not yield that error, but creating a new python file with the correct imports will create the error: NoneType Object does not have attribute parse_known_args()