# Airline Model - DAML

**URL:** <https://forum.canton.network/t/airline-model-daml/4247>\
**Category:** App Development\
**Created:** [April 3, 2022, 7:50pm UTC](https://forum.canton.network/t/airline-model-daml/4247 "2022-04-03T19:50:36Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![Mate\_Varga](https://yyz2.discourse-cdn.com/flex034/user_avatar/forum.canton.network/mate_varga/32/2308_2.png) [@Mate\_Varga](https://forum.canton.network/u/Mate_Varga)\
**Post date:** [April 4, 2022, 6:00am UTC](https://forum.canton.network/t/airline-model-daml/4247/2 "2022-04-04T06:00:50Z")

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Hi Erum

As @a_putkov replied to you [here](https://discuss.daml.com/t/airline-model-daml-code/4215/6), `===` is the infix version of the [assertEq](https://docs.daml.com/daml/stdlib/DA-Assert.html#function-da-assert-asserteq-7135) function. Which means, these two lines are checking and making sure that the CheckIn exercise is performed with a flight that matches the `flightNumber` and `airline` data stored on the ticket. If the values are not equal the rest of the exercise - checking for the seat’s Class, creating a BoardingPass and exercising AssingSeat on it - won’t be performed.

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_[View the full topic](https://forum.canton.network/t/airline-model-daml/4247)._