Sorting documentation claims that sorting algorithm is only using < comparisons
https://docs.python.org/3/howto/sorting.html#odd-and-ends
https://docs.python.org/3/library/stdtypes.html#list.sort

When __lt__ implementation is missing, you get an exception
class Foo:
    pass
sorted([Foo(), Foo(), Foo()])
TypeError: '<' not supported between instances of 'Foo' and 'Foo'

However, if implement __gt__ method, you doesn't get an exception
class Foo:
    def __gt__(self, other):
        return False
sorted([Foo(), Foo(), Foo()])  # ok


Is it supposed to work like this? Or is it lack of documentation?