def _env_paths_to_names(envs):
reduced = {}<EOL>for env_name, env_data in envs.items():<EOL><INDENT>reduced[env_name] = _compute_paths_to_names(env_data)<EOL><DEDENT>return reduced<EOL>
Convert filepath(s) in each environment to filename for assertion.

Project instance will ensure that filepaths are absolute, but we want
assertion logic here to be independent of that (unless that's under test).

:param Mapping[str, Mapping]: environment data by name
:return Mapping[str, Mapping]: same as the input,
    but with conversion(s) performed