Determining if a word is an anagram of another
You need to check if each letter occurs the name number of times in both strings.

One method would be to sort the letters and compare the lists of letters for equality.

Here is my approach:

def is_anagram(test, original):
  return sorted(list(test.lower())) == sorted(list(original.lower()))


This algorithm is far from optimal runtime O(n*logn), but I have chosen it because of its simplicity.
For an Efficient algorithm see the comment of @corsiKa for a quite simple O(n) algorithm.