Doc Improvement: parameter age_limit of function reduce_size time unit unknown.

[PhilipMay]

I guess it is seconds.... but should be added to the docstring.

[tomMoral]

Hello,

Thanks for reporting the issue and sorry for the reply delay.

The age_limit attribute should be of type datetime.timedelta (as specified here: https://joblib.readthedocs.io/en/stable/generated/joblib.Memory.html#joblib.Memory.reduce_size).
Passing an integer raises an error:

from joblib import Memory

mem = Memory('.')

@mem.cache
def f():
    return

f()
mem.reduce_size(age_limit=0)

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[7], line 1
----> 1 mem.reduce_size(age_limit=0)

File ~/.local/miniconda/lib/python3.10/site-packages/joblib/memory.py:1141, in Memory.reduce_size(self, bytes_limit, items_limit, age_limit)
   1138     return
   1140 # Defers the actual limits enforcing to the store backend.
-> 1141 self.store_backend.enforce_store_limits(
   1142     bytes_limit, items_limit, age_limit
   1143 )

File ~/.local/miniconda/lib/python3.10/site-packages/joblib/_store_backends.py:303, in StoreBackendMixin.enforce_store_limits(self, bytes_limit, items_limit, age_limit)
    297 def enforce_store_limits(
    298         self, bytes_limit, items_limit=None, age_limit=None
    299 ):
    300     """
    301     Remove the store's oldest files to enforce item, byte, and age limits.
    302     """
--> 303     items_to_delete = self._get_items_to_delete(
    304         bytes_limit, items_limit, age_limit
    305     )
    307     for item in items_to_delete:
    308         if self.verbose > 10:

File ~/.local/miniconda/lib/python3.10/site-packages/joblib/_store_backends.py:343, in StoreBackendMixin._get_items_to_delete(self, bytes_limit, items_limit, age_limit)
    341 if age_limit is not None:
    342     older_item = min(item.last_access for item in items)
--> 343     deadline = datetime.datetime.now() - age_limit
    344 else:
    345     deadline = None

TypeError: unsupported operand type(s) for -: 'datetime.datetime' and 'int'

I am not sure I understand the issue, how would you specify the units?