python have lots of built-in functionsbut very often we need to create our own functions (we could refer to these functions as user-defined functionsin python function is defined using the def keyword functionname return example create function in separate file below you see simple function created in python add return listing basic python function the function adds numbers the name of the function is addand it returns the answer using the return statement the statement return [expressionexits functionoptionally passing back an expression to the caller return statement with no arguments is the same as return none note that you need to use colon ":at the end of line where you define the function note also the indention used add here you see python script where we use the function add return add print listing creating and using python function