def make_keys_multicol(columns_to_update_lst):
    """
        returns keys to be updated and new names of columns to be updated
        :param columns_to_update_lst:
        :return joined_str: part of postgres query with keys. E.g. "col1=c.updatecol1 , col2=c.updatecol2"
                update_lst: list of new column names in intermediate tables. E.g. [updatecol1, updatecol2]
    """
    key_equal = []
    update_lst = []
    for key in columns_to_update_lst:
        temp_str = key + " = c.update" + key
        update_lst.append("update" +key)
        key_equal.append(temp_str)
    joined_str = ",".join(key_equal)
    return joined_str, update_lst