Design the sequence diagram for the use case $$create contract$$ following

these interactions:

$$ The insurance agent enters the identifier of the customer.

$$ If he is an old customer, the customer data are displayed on the user

interface.

$$ If not, the insurance agent enters the customer data, and the customer

will be added to the database.

$$ The insurance agent enters the vehicle data.

$$ The insurance agent enters the contract data.

$$ A message will be displayed on the user interface "confirmation $($Y $/$ N$)$

$$ If the user enters $($Y$)$ the vehicle and the contract will be added to the

database.