stock.picking.type has 3 type of opration 

1) Receipt -> incomming

2) Delivery -> outgoing

3) Internal Transfer -> internal

As per your requirement and attrs domain you want to see your custom button for delivery and internal. so we nee do hide button for incoming (receipt) and  domain would be following

attrs="{'invisible': [('picking_type_code', '=', 'incoming')]

Thanks & Regards,

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I use delivery in 2 steps  and the picking operation (PICK)is the first one to be processed

i try this but it not worked :

attrs="{ 'invisible': [ ('picking_type_id.sequence_code ', '!=', 'PICK')]}"/>