New device class don't appear in HA

in my integrations/mqtt.yaml I have following

mqtt: 
  binary_sensor: !include_dir_list ../entities/binary_sensors
  light: !include_dir_list ../entities/lights
  sensor: !include_dir_list ../entities/sensors
  pump: !include_dir_list ../entities/pumps
  switch: !include_dir_list ../entities/switches

I add new device pump, then I create /entities/pumps folder and create few devices in this folder, but they don’t appear in my HA yet.
Everything looks absolutely the same as with lights, but not working. What is missing?

Have you restarted HA?

There’s no pump domain, and no MQTT pump integration.

If you’d run ha core check it would have told you about that.

It is complicated to do new domain for a new device? I supposed it should be as simple as copy lights and rename it.