According to the doc:

    :class:`partial` objects are like :class:`function` objects in that they are callable, weak referencable, and can have attributes.

I don't understand why "weak" here, and it's the only occurence of "weak referencable" in the documentation.

I don't see an object in Python being referencable but NOT weak referencable, do I miss something obvious here?

```

In [1]: import weakref                                                                                                    

In [2]: class A: 
   ...:     __slots__ = ()                                                                                                

In [3]: weakref.ref(A())                                                                                                  
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-3-60f73a442704> in <module>
----> 1 weakref.ref(A())

TypeError: cannot create weak reference to 'A' object

```

TIL.

So it really make sense in this context to tell a functools.partial is weak referencable?

I think yes.

Instances of many builtin types are not weak referencable.

>>> weakref.ref(0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: cannot create weak reference to 'int' object
>>> weakref.ref([])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: cannot create weak reference to 'list' object