How do I process True only when the object is a list or tuple, and False when the string is false?

First, the second factor of isinstance() can be tuple-type assert isinstance(lst, list) or isinstance(lst, tuple) can be reduced to assert is instance(lst, (list, tuple)).

And when you use the ASSERT, I think assert not isinstance(lst, basestring) I think it's a better way to use it (Please change to string since Python 3 cannot use basestring)

If you write it like the way you asked, Although it is not subclass in list/tuple, assertionError occurs in other types that behave like list/tuple.