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Simplify conditional expressions

Co-authored-by: Andrew Murray <[email protected]>

src/PIL/ImageGrab.py

@@ -164,9 +164,7 @@ def grabclipboard():
         else:  # Session type check failed
             sessiontype = None
 
-        if shutil.which("wl-paste") and (
-            (sessiontype == "wayland") or (sessiontype is None)
-        ):
+        if shutil.which("wl-paste") and sessiontype in ["wayland", None]:
             output = subprocess.check_output(["wl-paste", "-l"]).decode()
             mimetypes = output.splitlines()
             if "image/png" in mimetypes:
@@ -179,9 +177,7 @@ def grabclipboard():
             args = ["wl-paste"]
             if mimetype:
                 args.extend(["-t", mimetype])
-        elif shutil.which("xclip") and (
-            (sessiontype == "x11") or (sessiontype is None)
-        ):
+        elif shutil.which("xclip") and sessiontype in ["x11", None]:
             args = ["xclip", "-selection", "clipboard", "-t", "image/png", "-o"]
         else:
             msg = "wl-paste or xclip is required for ImageGrab.grabclipboard() on Linux"