Why won't my code work?

Something is wrong.

Miss a letter, a semi-colon, a quote, or a curly bracket and your code goes haywire. Triple-check every line. If it doesn't work, you made a mistake. There is no other reason. Computers are that exact.

Try and debug it. We all can't be perfect first try.

Because it's the wrong one

You have the statement assigning dayofweek indented to be part of the while loop above it.  It doesn't belong there, and should be indented to the same level as the return statement below it. 

You don't need the while loops at all, by the way.  Those are things you do in languages based on C, where % is a remainder operator.  Delete both while statements, keep the dayofweek variable, and change the return to:

    return dayofweek[e % 7]

Don't try that in C/C++, Java or C# when e%7 can be negative if e<0; but it does the right thing in Python.

The first while condition does not assign dayofweek.  That condition checks True and then the code goes to return dayofweek