Fix dangerous default argument

dangerous_default_arg_test.py

@@ -2,18 +2,30 @@
 import os
 
 
-def some_func(arg1, arg2, arg3=[1, 2, 3], arg4=None, arg5={1,2}):
+def some_func(arg1, arg2, arg3=None, arg4=None, arg5=None):
     """
     Some docstring to ensure docstring stay at its position
     """
+    if arg3 is None:
+        arg3 = [1, 2, 3]
+    if arg5 is None:
+        arg5 = {1,2}
     print("I am a function!")
 
-    def some_other_func(arg=[1,2,3]):
+    def some_other_func(arg=None):
         """Nested function to ensure indentation doesn't get messed up"""
+        if arg is None:
+            arg = [1,2,3]
 
         x = [1,2,3]; y={1, 2, 3}; z={'a': 1, 'b': 2}; t=(1, 2, 3)
-        def another_nested_function(danger_one=x, danger_two=y, danger_three=z, xyz=None, safe_four=t):
+        def another_nested_function(danger_one=None, danger_two=None, danger_three=None, xyz=None, safe_four=t):
             """Another deeply nested function."""
+            if danger_one is None:
+                danger_one = x
+            if danger_two is None:
+                danger_two = y
+            if danger_three is None:
+                danger_three = z
             return
 
         return arg