@lower_builtin('is not', types.Any, types.Any)
def generic_is_not(context, builder, sig, args):
 is_impl = context.get_function('is', sig)
 return builder.not_(is_impl(builder, args))

@ lower_builtin ( 'is not' , types . Any , types . Any ) def generic_is_not ( context , builder , sig , args ) : is_impl = context . get_function ( 'is' , sig ) return builder . not_ ( is_impl ( builder , args ) )
implement x is not y as not .