#NEWLINE# def unregister( self , observer ) : #NEWLINE# #INDENT# LOG . debug ( 'Dettaching observer: %(ob)s from subject: %(sub)s' , { #NEWLINE# #INDENT# 'ob' : observer . __class__ . __name__ , #NEWLINE# 'sub' : self . __class__ . __name__ , #NEWLINE# #UNINDENT# } ) #NEWLINE# if ( observer in self . _observers ) : #NEWLINE# #INDENT# self . _observers . remove ( observer ) #NEWLINE# #UNINDENT# else : #NEWLINE# #INDENT# raise ValueError ( _ ( 'Observer: %(ob)s is not attached to subject: %(sub)s' ) , { #NEWLINE# #INDENT# 'ob' : observer . __class__ . __name__ , #NEWLINE# 'sub' : self . __class__ . __name__ , #NEWLINE# #UNINDENT# } )