diff --git a/Makefile b/Makefile
index a1edc88..f8971cc 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@ all: cython
 
 .PHONY: black
 black:
-	black .
+	black msgpack/ test/
 
 .PHONY: cython
 cython:
diff --git a/msgpack/fallback.py b/msgpack/fallback.py
index fa2f3a8..388a5ab 100644
--- a/msgpack/fallback.py
+++ b/msgpack/fallback.py
@@ -2,7 +2,6 @@
 
 import sys
 import struct
-import warnings
 
 
 PY2 = sys.version_info[0] == 2