Update code in spread

snippets/spread.md

@@ -11,13 +11,10 @@ Loop over elements, use `list.extend()` if the element is a list, `list.append()
 def spread(arg):
   ret = []
   for i in arg:
-    if isinstance(i, list):
-      ret.extend(i)
-    else:
-      ret.append(i)
+    ret.extend(i) if isinstance(i, list) else ret.append(i)
   return ret
 ```
 
 ```py
-spread([1,2,3,[4,5,6],[7],8,9]) # [1,2,3,4,5,6,7,8,9]
-```
+spread([1, 2, 3, [4, 5, 6], [7], 8, 9]) # [1, 2, 3, 4, 5, 6, 7, 8, 9]
+```