I will consider this as a mistake. In the criteriaFind() implementation, it mentions by example that the method should be able to accept the argument
string "Carrier='SpeedyAir',Origin='SFO'". Strictly speaking, there is no such field name as "Origin" in the database. The correct form should be written as "Carrier='SpeedyAir',Origin Airport='SFO'". The method I implement will return field name not found message. This is my thought.