Research: Python: handling mutables as arguments and as default arguments

research/python.md

@@ -97,6 +97,10 @@ Python encourages polymorphism:
 So remember that when [copying](https://stackoverflow.com/questions/2612802/how-to-clone-or-copy-a-list#2612815)
 or referencing a list.
 
+Also, [take care with handling mutables as arguments and as default arguments](http://www.thedigitalcatonline.com/blog/2015/02/11/default-arguments-in-python/),
+also explained [here](https://docs.python.org/3/tutorial/controlflow.html#default-argument-values) and [here](https://docs.python-guide.org/writing/gotchas/)
+(common gotchas).
+
 ### Threads
 
 From [GlobalInterpreterLock](https://wiki.python.org/moin/GlobalInterpreterLock):