Provided solution to evaluate.

nim.py

@@ -68,7 +68,13 @@ def evaluate(heap_sizes):
     >>> evaluate([9, 12, 3, 7])
     <Evaluation.LOSS: 'LOSS'>
     """
-    return Evaluation.LOSS  # Stub
+    if len(heap_sizes) > 1:
+        single_heap = convert_to_single_heap_using_builtin(heap_sizes[0],
+                                                           heap_sizes[1])
+        return evaluate([single_heap] + heap_sizes[2:])
+    else:
+        return Evaluation.WIN if len(heap_sizes) == 0 or heap_sizes[0] == 0 \
+            else Evaluation.LOSS
 
 
 def make_computer_move(position):