OpenERP get next Sequence number

[EP-Fan]

OpenERP gives a sequence number when we saved a record. i have done that module.as per that module when i create a worker then load employee number as EMP001,EMP002..My requirment is this. When I'm going to create a new employee then need to show next sequence number as a read only field.for ex : when i'm going to create a 9th employee then need to show EMP009 in my emp no field.my current codes uploaded to below locationhttps://github.com/priyankahdp/openerp/tree/openerp