The graded function is inactive

Please help: I am working with the graded function in the browser, I accidentally typed something in the area outside of the block # YOUR CODE STARTS HERE #YOUR CODE ENDS HERE
then the whole function does not have python reserved keywords highlighted anymore and when the cell is run, it is complained that function name is undefined.
Please help so I can have the fresh copy of the function. Thanks very much in advance

This issue has been fixed. In the assignment workspace, I select “File → Revert to checkpoint” to revert back to the previous checkpoint with the correct function definition and I completed the Initialization assignment in SDP Course 2