code: func (c deploymentChecker) Condition(node *blockNode) (bool, error) {
  	conditionMask := uint32(1) << c.deployment.BitNumber
  	version := uint32(node.version)
  	return (version&vbTopMask == vbTopBits) && (version&conditionMask != 0),
  		nil
  }
docs: // Condition returns true when the specific bit defined by the deployment
  // associated with the checker is set.
  //
  // This is part of the thresholdConditionChecker interface implementation.