Ability to manually specify command_path for CLI Python modules

My Python code must be run as a module. So the code where I define cli command is in __main__.py, and I run the script with python -m foo.

The problem is that Click displays the help instructions as:

Usage: __main__.py [OPTIONS] COMMAND [ARGS]...

But I would like:

Usage: python -m foo [OPTIONS] COMMAND [ARGS]...

I tried this:

@click.group(name='python -m foo')
def main():
    pass

which as no effect,

and also this:

@click.group()
@click.pass_context
def main(ctx):
    ctx.command_path = 'python -m foo'

which fails with AttributeError: can't set attribute.

The ability to manually specify the command_path is necessary to work with CLI Python modules or other particular scenarios.

[roipoussiere]

For anyone looking for the same behavior, here is a simple working example:

import click

@click.group()
def main():
    pass

if __name__ == '__main__':
    main(prog_name='python -m foo')

@davidism in the example you provided I was not able to guess what exactly was the imported cli.

[roipoussiere]

Thanks for your help. Is there an example of that in the docs?