#NEWLINE# def fdiff( self , argindex = 1 ) : #NEWLINE# #INDENT# if ( argindex == 1 ) : #NEWLINE# #INDENT# return ( ( - 1 ) / ( 1 + ( self . args [ 0 ] ** 2 ) ) ) #NEWLINE# #UNINDENT# else : #NEWLINE# #INDENT# raise ArgumentIndexError ( self , argindex )