python: reformat with black-23.7.0-2.fc39.noarch

The base image for the "check-tree" test got bumped to Fedora 39.  This
brings a new python-black version (23.7.0 vs. 22.8.0) and requires
reformatting.

Maybe we should stick to 22.8.0, via `pip install`. But it seems better
to just follow the latest black version (the one from current Fedora).

So do the reformatting instead.

https://black.readthedocs.io/en/stable/change_log.html#id38

examples/python/gi/gmaincontext.py

@@ -71,6 +71,7 @@ def error_is_cancelled(e):
 
 ###############################################################################
 
+
 # A Context manager for running a mainloop. Of course, this does
 # not do anything magically. You can run the context/mainloop without
 # this context object.
@@ -265,7 +266,6 @@ def create_nmc(dbus_connection):
 
 
 def make_call(nmc):
-
     log("[make_call]: make some async D-Bus call")
 
     if not nmc:
@@ -273,7 +273,6 @@ def make_call(nmc):
         return
 
     with MainLoopRun("make_call", nmc.get_main_context(), 1) as r:
-
         # There are two reasons why async operations are preferable with
         # D-Bus and libnm:
         #
@@ -405,7 +404,6 @@ def destroy_nmc(nmc_holder, destroy_mode):
             raise Exception("Failure to destroy NMClient: something keeps it alive")
 
     else:
-
         if destroy_mode == 1:
             ctx = GLib.MainContext.default()
         else: