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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def fetch_all_first_values(session: Session, select_statement: Select) -> List[Any]: """ Returns a list of the first values in each row returned by a ``SELECT`` query. A Core version of this sort of thing: http://xion.io/post/code/sqlalchemy-query-values.html Args: session: SQLAlchemy :class:`Session` object select_statement: SQLAlchemy :class:`Select` object Returns: a list of the first value of each result row """

    rows = session.execute(select_statement)  # type: ResultProxy
    try:
        return [row[0] for row in rows]
    except ValueError as e:
        raise MultipleResultsFound(str(e))