close files properly after patching

Randomizer.py

@@ -2579,7 +2579,7 @@ def randomize_game(graph):
     patch_game()
 
 def patch_game():
-    global FileName, BaseName
+    global FileName, BaseGame
     CreditsOffsets = {
         'ChargeBeam': 7655617,
         'WideBeam': 7655725,
@@ -2616,20 +2616,22 @@ def patch_game():
         os.system('.\\armips\\armips.exe "Metroid Fusion Open Randomizer.asm" -root ".\\data\\asm" -sym ".\\temp.sym"')
         os.replace('.\\data\\MFOR.gba', '.\\seeds\\{}.gba'.format(FileName))
     else:
-        source = open(BaseName, 'rb')
+        error = False
-        target = open(os.path.join('.', 'seeds', '{}.gba'.format(FileName)), 'wb')
+        with open(BaseGame, 'rb') as source:
-        patch = open(os.path.join('.', 'data', 'MFOR.bps'), 'rb')
+            with open(os.path.join('.', 'seeds', '{}.gba'.format(FileName)), 'wb') as target:
+                with open(os.path.join('.', 'data', 'MFOR.bps'), 'rb') as patch:
                     try:
                         apply_to_files(patch, source, target)
-        except:
+                    except Exception:
-          target.close()
+                        error = True
-          os.unlink(os.path.join('.', 'seeds', '{}.gba'.format(FileName)))
+        if error:
+            os.remove(os.path.join('.', 'seeds', '{}.gba'.format(FileName)))
             print('Error: failed to patch game with base patch!')
             sys.exit(1)
 
         checksum = fileHash(os.path.join('.', 'seeds', '{}.gba'.format(FileName)))
         if checksum != 2455114263:
-            os.unlink(os.path.join('.', 'seeds', '{}.gba'.format(FileName)))
+            os.remove(os.path.join('.', 'seeds', '{}.gba'.format(FileName)))
             print('Error: Base patch file has been modified. Please go to https://metroidconstruction.com/ and re-download MFOR.')
             sys.exit(1)
 
@@ -2865,13 +2867,13 @@ def patch_game():
         with open(os.path.join('.', 'seeds', '{}.gba'.format(FileName)), 'rb') as target:
             targetdata = target.read()
 
-        patch = open(os.path.join('.', 'seeds', '{}.bps'.format(FileName)), 'wb')
-            
         blocksize = (len(sourcedata) + len(targetdata)) // 1000000 + 1
         print("Using blocks of {0} bytes".format(blocksize))
 
         iterable = diff_bytearrays(blocksize, sourcedata, targetdata)
+        with open(os.path.join('.', 'seeds', '{}.bps'.format(FileName)), 'wb') as patch:
             write_bps(bps_progress(iterable), patch)
+
     print('')
 
     ItemNames = [