Black: Black adds unnecessary parentheses around tuples of one element

[layoaster]

Operating system: Ubuntu 19.04
Python version: 3.7.2
Black version: 19.3b0
Does also happen on master: yes

Black forces the use of parentheses on tuples of one element without parentheses. Check the black diff below:

class LivenessProbe(View):
"""Liveness probe handler."""
-    methods = "GET",
+    methods = ("GET",)
def dispatch_request(self) -> Response:

[JelleZijlstra]

I'd say this is a feature, not a bug. A single comma is easy to miss, and the parentheses make it clearer that it's a tuple.

[andrewmwilson]

The fact that methods = "GET", is valid python syntax is incredibly annoying. It causes so many hard-to-find bugs and is basically useless.

[JelleZijlstra]

No action required here.