USING PYTHON: In this problem, you want to write a function revdict that takes a dictionary D and returns a dictionary R that reverses D by mak- ing the keys into values and the values into keys. For example if D[k] = v we would want R[v] = k.

Theres a problem. The keys in a dictionary are unique while several keys may have the same value. To fix this, well let R[v] be a list of the keys that have value v. So, if

D = { A:1, B:2, C:1} 

well have R[2] = [B] and R[1] = [A, C]. Write the function revdict. Include sorce code for the function and and some test runs to show it works.