try assigning to itself

Author: stellalin7

asv_bench/benchmarks/attrs_caching.py

@@ -15,7 +15,7 @@ def setup(self):
         self.cur_index = self.df.index
 
     def time_get_index(self):
-        self.foo_index = self.df.index
+        self.df.index = self.df.index
 
     def time_set_index(self):
         self.df.index = self.cur_index