Utility method

    :param dict_of_list:
    :param key:
    :param parser:
    :return:

def insert_element_to_dict_of_list(dict_of_list, key, parser):
    """
    Utility method

    :param dict_of_list:
    :param key:
    :param parser:
    :return:
    """
    if key in dict_of_list.keys():
        dict_of_list[key].append(parser)
    else:
        dict_of_list[key] = [parser]