docs: def total_ordering(cls):  # pragma: no cover
      """Class decorator that fills in missing ordering methods"""
      convert = {
          '__lt__': [('__gt__', lambda self, other: not (self < other or self == other)),
                     ('__le__', lambda self, other: self < other or self == other),
                     ('__ge__', lambda self, other: not self < other)],
          '__le__': [('__ge__', lambda self, other: not self <= other or self == other),
                     ('__lt__', lambda self, other: self <= other and not self == other),
                     ('__gt__', lambda self, other: not self <= other)],
          '__gt__': [('__lt__', lambda self, other: not (self > other or self == other)),
                     ('__ge__', lambda self, other: self > other or self == other),
                     ('__le__', lambda self, other: not self > other)],
          '__ge__': [('__le__', lambda self, other: (not self >= other) or self == other),
                     ('__gt__', lambda self, other: self >= other and not self == other),
                     ('__lt__', lambda self, other: not self >= other)]
      }
      roots = set(dir(cls)) & set(convert)
      if not roots:
          raise ValueError('must define at least one ordering operation: < > <= >=')
      root = max(roots)       # prefer __lt__ to __le__ to __gt__ to __ge__
      for opname, opfunc in convert[root]:
          if opname not in roots:
              opfunc.__name__ = opname
              opfunc.__doc__ = getattr(int, opname).__doc__
              setattr(cls, opname, opfunc)
      return cls