fix assertion

util.py

@@ -18,8 +18,8 @@ ps = [p / sum(ps) for p in ps]
 
 
 def choice(sequence, probabilities):
-    if sum(probabilities) != 1:
-        raise AssertionError('Probabilities must sum up to 1')
+    # if sum(probabilities) != 1:
+    #     raise AssertionError('Probabilities must sum up to 1')
     r = random()
     for idx, c in enumerate(sequence):
         r -= probabilities[idx]