According to the book changes (egonSchiele#144)

OleksandrDanylchenko · egonSchiele · commit 03db2855d609 · 2019-10-30T16:31:21.000-05:00
Changed the name of the variable according to the book
diff --git a/08_greedy_algorithms/python/01_set_covering.py b/08_greedy_algorithms/python/01_set_covering.py
@@ -13,8 +13,8 @@
 while states_needed:
   best_station = None
   states_covered = set()
-  for station, states in stations.items():
-    covered = states_needed & states
+  for station, states_for_station in stations.items():
+    covered = states_needed & states_for_station
     if len(covered) > len(states_covered):
       best_station = station
       states_covered = covered
