code: def get_validator_change(cls, bigchain):
          
          latest_block = bigchain.get_latest_block()
          if latest_block is None:
              return None
          return bigchain.get_validator_change(latest_block['height'])
docs: Return the validator set from the most recent approved block
  
          :return: {
              'height': <block_height>,
              'validators': <validator_set>
          }