def _parse_query(database_engine, search_term):

    # Pull out the individual words, discarding any non-word characters.
    results = re.findall(r"([\w\-]+)", search_term, re.UNICODE)

    if isinstance(database_engine, PostgresEngine):
        return " & ".join(result + ":*" for result in results)
    elif isinstance(database_engine, Sqlite3Engine):
        return " & ".join(result + "*" for result in results)
    else:
        # This should be unreachable.
        raise Exception("Unrecognized database engine")
Takes a plain unicode string from the user and converts it into a form
dataset/ETHPy150Open matrix-org/synapse/synapse/storage/search.py/_parse_query