#NEWLINE# def slider( self ) : #NEWLINE# #INDENT# previous1 = previous2 = None #NEWLINE# for token in self . source : #NEWLINE# #INDENT# if ( previous1 is not None ) : #NEWLINE# #INDENT# ( yield ( previous2 , previous1 , token ) ) #NEWLINE# #UNINDENT# previous2 = previous1 #NEWLINE# previous1 = token #NEWLINE# #UNINDENT# ( yield ( previous2 , previous1 , None ) )