<PLEASE USE THE FOLLOWING TEMPLATE TO HELP YOU CREATE A GREAT POST!>
<Below this line, add a link to the EXACT exercise that you are stuck at.>
<In what way does your code behave incorrectly? Include ALL error messages.>
<What do you expect to happen instead?>```python
Replace this line with your code.
<do not remove the three backticks above when i do "print print_grades(grades) " instead of "for grade in grades: print grade" why is there a "none" at the end of the printed out grades