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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 delete_session(sid_s):
 """Delete entries in the data- and kvsessionstore with the given sid_s. On a successful deletion, the flask-kvsession store returns 1 while the sqlalchemy datastore returns None. :param sid_s: The session ID. :returns: ``1`` if deletion was successful. """

    # Remove entries from sessionstore
    _sessionstore.delete(sid_s)
    # Find and remove the corresponding SessionActivity entry
    with db.session.begin_nested():
        SessionActivity.query.filter_by(sid_s=sid_s).delete()
    return 1