The code differs as you can see my code below I don't know where to add this command:.
'refrence : self.refrence' because he added 'patient_id : self.patient_id.id'

@api.model_create_multi
def create(self, vals_list):
for one_vals in vals_list:
if one_vals.get("reference", _("New")) == _("New"):
Sequence = self.env["ir.sequence"]
one_vals["reference"] = Sequence.next_by_code("mgmtsystem.action")
actions = super().create(vals_list)
actions.send_mail_for_action()
return actions