Python3 pass lists to function with functools.lru_cache

This fails because a list is unhashable. This would make it hard for Python to know what values are cached. A way to fix this is by converting lists to tuples before passing them to a cached function: since tuples are immutable and hashable, they can be cached.

TL;DR

Use a tuple instead of a list:

>>> @lru_cache(maxsize=2)
... def my_function(args):
...     pass
...
>>> my_function([1,2,3])
Traceback (most recent call last):
  File "<input>", line 1, in <module>
    my_function([1,2,3])
TypeError: unhashable type: 'list'

>>> # TO FIX: use a tuple 

>>> my_function(tuple([1,2,3]))
>>>