def clean_locale(configuration, locale):
    """
    Strips out the warning from all of a locale's translated po files
    about being an English source file.
    Iterates over machine-generated files.
    """
    dirname = configuration.get_messages_dir(locale)
    if not dirname.exists():
        # Happens when we have a supported locale that doesn't exist in Transifex
        return
    for filename in dirname.files('*.po'):
        clean_file(configuration, dirname.joinpath(filename))