if hashable

[Gribouillis]

You could use collections.abc.Hashable

>>> from collections.abc import Hashable
>>> isinstance('spam', Hashable)
True
>>> isinstance([], Hashable)
False

Well, thinking again, it doesn't seem to work well for what you want to do

>>> from collections.abc import Hashable
>>> isinstance((1, []), Hashable)
True
>>> {(1, []): 3}
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'list'

Then a reason to prefer hash() over the dict is that it doesn't attempt to build a dictionary instance.