code: def _iter_enum_constant_ids(eid):
      
      for bitmask in _iter_bitmasks(eid):
          for value in _iter_enum_member_values(eid, bitmask):
              for cid, serial in _iter_serial_enum_member(eid, value, bitmask):
                  yield cid
docs: Iterate the constant IDs of all members in the given enum