(I need help coding problem; an explanation would be appreciated. In Python, please, Thank you.)

Implement a function `roll` that takes in a string and "rolls" it as follows.

~~~ Input: hello Output: elloh

Input: world Output: orldw

Input: abcd Output: bcda

Input: // Empty String Output: // Empty String ~~~

// YOUR CODE HERE ???

//BEGIN TEST testWithMessage(roll(""),"", "Test1") testWithMessage(roll("z"),"z", "Test2") testWithMessage(roll("hello"),"elloh", "Test3") testWithMessage(roll("ananas"),"nanasa", "Test4") testWithMessage(roll("za"),"az", "Test5") passed(5) //END TEST