Return names of immediate child directories

def get_child_directories(path):
    """Return names of immediate child directories"""
    if not _is_valid_directory(path):
        raise exceptions.InvalidDirectory

    entries = os.listdir(path)
    directory_names = []

    for entry in entries:
        abs_entry_path = os.path.join(path, entry)
        if _is_valid_directory(abs_entry_path):
            directory_names.append(entry)

    return directory_names