code: def scale_in(self, blocks):
          
          to_kill = self.blocks[:blocks]
          if self.provider:
              r = self.provider.cancel(to_kill)
          return r
docs: Scale in the number of active blocks by specified amount.
  
          The scale in method here is very rude. It doesn't give the workers
          the opportunity to finish current tasks or cleanup. This is tracked
          in issue #530
  
          Raises:
               NotImplementedError