Python SQLAlchemy: stored procedura + parameter

#!/usr/bin/python3.5

# import
import sqlalchemy;

sqlhost = "mysql://root:test@localhost:3306/httptree?autocommit=true&use_unicode=True&charset=utf8";

engine = sqlalchemy.create_engine(sqlhost);

ses = "20190119152018667518";

sessionid = engine.execute("CALL `httptree`.`spGetIdForSid`(%(session)s)", {"session":ses}).scalar();

print("sessionid=" + str(sessionid));