code: def add_known_devices(self, plm):
          
          from insteonplm.devices import ALDBStatus
          for addr in self._saved_devices:
              if not self._devices.get(addr):
                  saved_device = self._saved_devices.get(Address(addr).id, {})
                  cat = saved_device.get('cat')
                  subcat = saved_device.get('subcat')
                  product_key = saved_device.get('firmware')
                  product_key = saved_device.get('product_key', product_key)
                  device = self.create_device_from_category(
                      plm, addr, cat, subcat, product_key)
                  if device:
                      _LOGGER.debug('Device with id %s added to device list '
                                    'from saved device data.', addr)
                      aldb_status = saved_device.get('aldb_status', 0)
                      device.aldb.status = ALDBStatus(aldb_status)
                      aldb = saved_device.get('aldb', {})
                      device.aldb.load_saved_records(aldb_status, aldb)
                      self[addr] = device
          for addr in self._overrides:
              if not self._devices.get(addr):
                  device_override = self._overrides.get(Address(addr).id, {})
                  cat = device_override.get('cat')
                  subcat = device_override.get('subcat')
                  product_key = device_override.get('firmware')
                  product_key = device_override.get('product_key', product_key)
                  device = self.create_device_from_category(
                      plm, addr, cat, subcat, product_key)
                  if device:
                      _LOGGER.debug('Device with id %s added to device list '
                                    'from device override data.', addr)
                      self[addr] = device
docs: Add devices from the saved devices or from the device overrides.