human
I wrote the below code

    def _execute(pkg):
        spec_string = kwargs.get('when', pkg.name)
        provider_spec = parse_anonymous_spec(spec_string, pkg.name)
        for string in specs:
            for provided_spec in spack.spec.parse(string):
                if (pkg.name == provided_spec.name):
                    raise CircularReferenceError('depends_on', pkg.name)
                if (provided_spec not in pkg.provided):
                    pkg.provided[provided_spec] = set()
                pkg.provided[provided_spec].add(provider_spec)
    return _execute

What's a good function header?

=====
Here's a good function header?
assistant
#Here's a good function header.

@directive('provided')
def provides(*specs, **kwargs):