I am struggling to figure out how to write python code to accomplish this! please help

33.11 LAB: Fibonacci sequence Instructor note: The skills required for this lab are covered in Chapter 7. Functions. To successfully complete this lab, review the content of Chapter 7 , as well as the preceding chapters, and complete the Challenge Activities associated. The Fibonacci sequence begins with 0 and then 1 follows. All subsequent values are the sum of the previous two, ex: 0, 1, 1, 2, 3, 5, 8, 13 . Complete the fibonacci() function, which has an index n as parameter and returns the nth value in the sequence. Any negative index values should return -1. Ex: If the input is: 7 the output is: fibonacci(7) is 13 Note: Use a for loop and DO NOT use recursion. 360100.2631474.qx3zqy7