def list_to_file_name(file_list):
    """
    This function transforms the list that verify_file_exists function returns
    in a file name.

    :param file_list:       list

    :return:                String
    """

    name = file_list[0]
    for i in range(1, len(file_list)-1):
        name += '_' + file_list[i]
    name += '.' + file_list[-1]
    return name