def _env_filenames(filenames, env):
    """
    Extend filenames with ennv indication of environments.

    :param list filenames: list of strings indicating filenames
    :param str env: environment indicator

    :returns: list of filenames extended with environment version
    :rtype: list
    """
    env_filenames = []
    for filename in filenames:
        filename_parts = filename.split('.')
        filename_parts.insert(1, env)
        env_filenames.extend([filename, '.'.join(filename_parts)])

    return env_filenames
Extend filenames with ennv indication of environments.

    :param list filenames: list of strings indicating filenames
    :param str env: environment indicator

    :returns: list of filenames extended with environment version
    :rtype: list