MNT: use simpler set opretaions

tacaswell · timhoffm · web-flow · commit 0a33534f3b45 · 2020-03-30T14:17:48.000-04:00
Co-Authored-By: Tim Hoffmann &lt;2836374+timhoffm@users.noreply.github.com&gt;
diff --git a/lib/matplotlib/testing/decorators.py b/lib/matplotlib/testing/decorators.py
@@ -392,7 +392,7 @@ def decorator(func):
         _, result_dir = _image_directories(func)
         old_sig = inspect.signature(func)
 
-        if not all(k in old_sig.parameters for k in {"fig_test", "fig_ref"}):
+        if not {"fig_test", "fig_ref"}.issubset(old_sig.parameters):
             raise ValueError("The decorated function must have at least the "
                              "parameters 'fig_ref' and 'fig_test', but your "
                              f"function has the signature {old_sig}")
