Create a module and name it Lastname_Firstname_final.py. For example, John Smith's module would be Smith_John_final.py. In the module, add the following functions: 4. Write a function named problem4 that prompts the user for a sequence of integers and appends them to a list. Each integer can appear only once in the list. You need to ask the user to re-enter a different integer if the entered integer already exists in the list. Calculate and return the sum of the list. Call the function and display the return result. You may test it with the test case: if input sequence 1, 2, 3, 4, 5, then your function should return 15. (10 pts)