Hi Erum
As @a_putkov replied to you here, === is the infix version of the assertEq 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.