I am trying to automatically create a date using a function field to show us the date a contract will expire. I saw other topics discussing similar needs but I couldn't get their suggestions to work. 

To create this date I want to use a date field that specifies the date the contract begins and add on the number of years selected in a dropdown (1 or 3). 

Below is the function I have created but I receive this error "You used the wrong type of data in an argument. Check what you entered between the parentheses of your functions to make sure you put the right kind of data in the right place."

Adddate(${Service Contracts.Contract Begin Date},${Service Contracts.Contract Terms (Years)},'YEARS')

What do you think?

Thank you