def list_existing_tables(project_id, dataset_id):
    existing_tables = []
    all_table_objs = bq_utils.list_tables(project_id=project_id,
                                          dataset_id=dataset_id)
    for table_obj in all_table_objs:
        table_id = bq_utils.get_table_id_from_obj(table_obj)
        existing_tables.append(table_id)
    return existing_tables
def get_mapping_table_ids(project_id, combined_dataset_id):
    """
    returns all the mapping table ids found in the dataset
    :param project_id: project_id containing the dataset
    :param combined_dataset_id: dataset_id containing mapping tables
    :return: returns mapping table ids
    """
    table_objs = bq_utils.list_tables(combined_dataset_id,
                                      project_id=project_id)
    mapping_table_ids = []
    for table_obj in table_objs:
        table_id = bq_utils.get_table_id_from_obj(table_obj)
        if MAPPING_PREFIX in table_id:
            mapping_table_ids.append(table_id)
    return mapping_table_ids