def guard_invalid_slice(context, builder, typ, slicestruct):
 if typ.has_step:
  cgutils.guard_null(context, builder, slicestruct.step, (ValueError, 'slice step cannot be zero'))

def guard_invalid_slice ( context , builder , typ , slicestruct ) : if typ . has_step : cgutils . guard_null ( context , builder , slicestruct . step , ( ValueError , 'slice step cannot be zero' ) )
guard against *slicestruct* having a zero step .