def METHOD_NAME(source_dict, source_mapper, synchronize_pairs):
    # a simplified version of populate() used by bulk insert mode
    for l, r in synchronize_pairs:
        try:
            prop = source_mapper._columntoproperty[l]
            value = source_dict[prop.key]
        except exc.UnmappedColumnError as err:
            _raise_col_to_prop(False, source_mapper, l, source_mapper, r, err)
        try:
            prop = source_mapper._columntoproperty[r]
            source_dict[prop.key] = value
        except exc.UnmappedColumnError as err:
            _raise_col_to_prop(True, source_mapper, l, source_mapper, r, err)