doctest fix

Author: KrishnaSai2020

pandas/io/stata.py

@@ -178,7 +178,8 @@
 
 >>> itr = pd.read_stata('filename.dta', chunksize=10000)
 >>> for chunk in itr:
-... chunk.mean() # Operate on a single chunk
+... # Operate on a single chunk eg chunk.mean()
+... pass
 
 >>> import os
 >>> os.remove("./filename.dta")