Hello, i need to make a Automated Action on Odoo 12 to auto add the 3 chosen users as followers on create of contact. 

Image: https://ibb.co/yNXf6q3

Contact Manager = Field name: user_id
L2 Manager = Field name: x_studio_l2_manager
L3 Manager = Field name: x_studio_l3_manager

Any suggestion?

Thanks

--Update--

i found solution from  @arryph: Stackoverflow

record.message_subscribe(partner_ids=[record.user_id.partner_id.id, record.x_studio_l2_manager.partner_id.id, record.x_studio_l3_manager.partner_id.id])

Note:
I have the two extra fields type: res.users