code: def intersect(self, other: Iterable[Flag]) -> FrozenSet[Flag]:
          
          if Wildcard in self._defined:
              return frozenset(other)
          else:
              return self._defined & frozenset(other)
docs: Returns the subset of flags in ``other`` that are also in
          :attr:`.defined`. If the wildcard flag is defined, then all flags in
          ``other`` are returned.
  
          The ``&`` operator is an alias of this method, making these two
          calls equivalent::
  
              perm_flags.union(other_flags)
              perm_flags & other_flags
  
          Args:
              other: The operand flag set.