#NEWLINE# @ transition ( field = 'state' , source = BillingDocument . STATES . DRAFT , target = BillingDocument . STATES . ISSUED ) #NEWLINE# def issue( self , issue_date = None , due_date = None ) : #NEWLINE# #INDENT# self . archived_provider = self . provider . get_proforma_archivable_field_values ( ) #NEWLINE# super ( Proforma , self ) . issue ( issue_date , due_date )