def METHOD_NAME(self, folder):
    file_list = []
    for file_name in os.listdir(folder):
        if os.path.isfile(join_paths(
                folder, file_name)) and file_name.endswith(".npz"):
            file_list.append(join_paths(folder, file_name))
    return [i.split("/")[-1].split('.')[0] for i in file_list]