a little more refactor

scam.py

@@ -7,6 +7,7 @@ parser.add_argument("-a", "--all", dest="show_all_settings", action="store_true"
 clargs = parser.parse_args()
 
 
+
 SHOWN_SETTINGS = {
     "image_background": "Background",
     "threshold": "Threshold",
@@ -21,6 +22,8 @@ ENFORCED_SETTINGS = [
 ]
 
 
+
+import itertools
 import wx
 
 try:
@@ -139,7 +142,7 @@ class MainPanel(wx.Panel):
         new_cfg = self.make_cfg()
         print("\nold config:\n", old_cfg)
         print("\nnew config:\n", new_cfg)
-        print("\nunchanged\n" if old_cfg == new_cfg else "changed")
+        print("\nunchanged\n" if old_cfg == new_cfg else "\nchanged\n")
 
 
     def on_save_cfg(self, event):
@@ -179,16 +182,8 @@ def printable(val):
 
 
 def filter_dict(d, *args):
-    allkeys = []
-    for keys in args:
-        allkeys.extend(keys)
-
-    res = {k: v for k, v in d.items() if k in allkeys}
-    for k in allkeys:
-        if k not in res:
-            res[k] = None
-
-    return res
+    allkeys = itertools.chain.from_iterable(args)
+    return {k: d.get(k) for k in allkeys}