Fix typo

Author: gaffney2010

axelrod/match.py

@@ -130,7 +130,7 @@ def _cache_update_required(self):
         A boolean to show whether the deterministic cache should be updated.
         """
         return (
-            not self.is_stochastic
+            not self._stochastic
             and not self.noise
             and self._cache.mutable
             and not (any(Classifiers["stochastic"](p) for p in self.players))
@@ -195,9 +195,7 @@ def play(self):
                 p.set_seed(self._random.random_seed_int())
         result = []
         for _ in range(turns):
-            plays = self.simultaneous_play(
-                self.players[0], self.players[1], self.noise
-            )
+            plays = self.simultaneous_play(self.players[0], self.players[1], self.noise)
             result.append(plays)
 
         if self._cache_update_required: