I am trying to use a method to return my domain. Any advice?

Not working this way.

The client_id and client_id.id both return integers. When I hard code an example such as 

domain="[('client_id.id','=', 5)]"

Everything works. I think it is an encoding thing or formatting issue of what I am returning. 

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@api.model

def _getClientId(self):

    client_id = self.client_id.id

    domain = "[('client_id.id','='," + " " + str(client_id) + ")]"

    return domain

selected_review = fields.Many2one('something.something', domain=_getClientId)