Replicate 2.x arbitrary sorting logic in Python 3

sort_mixed_types.py

class MixedTypeKey:
    """Sort key for mixed type lists in Python 3

    >>> sorted([None, ..., 1, 1j, "", (), {}, []])
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    TypeError: unorderable types: ellipsis() < NoneType()
    >>> sorted([None, ..., 1, 1j, "", (), {}, []], key=MixedTypeKey)
    [None, Ellipsis, 1, 1j, '', (), {}, []]
    """
    def __init__(self, k):
        self._sort_key = k
        self._type_name = self._get_fully_qualified_name(k)

    def _get_fully_qualified_name(self, k):
        k_type = type(k)
        # Use __qualname__ if available, __name__ otherwise
        try:
            k_name = k_type.__qualname__
        except AttributeError:
            k_name = k_type.__name__
        return k_type.__module__ + "." + k_name

    def __lt__(self, other):
        # Try standard sorting first
        sort_key = self._sort_key
        try:
            other_sort_key = other._sort_key
        except AttributeError:
            other_sort_key = other
        try:
            return sort_key < other_sort_key
        except TypeError:
            pass
        # If that fails, sort by the fully qualified type names
        try:
            other_type_name = other._type_name
        except AttributeError:
            other_type_name = self._get_fully_qualified_name(other)
        return self._type_name < other_type_name