black is adding whitespace between print and ( with --target-version py27.
Test file:
from __future__ import print_function
print("hello world")
Result:
$ black t.py --target-version py27 --diff
--- t.py 2019-03-14 22:09:34.902887 +0000
+++ t.py 2019-03-14 22:10:21.022372 +0000
@@ -1,4 +1,4 @@
from __future__ import print_function
-print("hello world")
+print ("hello world")
reformatted t.py
All done! ✨ 🍰 ✨
1 file reformatted.
Operating system: OS X
Python version: 3.7.2
Black version: 19.3b0
Does also happen on master: yes