code: func (b *BlockChain) IsDeploymentActive(deploymentID uint32) (bool, error) {
  	b.chainLock.Lock()
  	state, err := b.deploymentState(b.bestChain.Tip(), deploymentID)
  	b.chainLock.Unlock()
  	if err != nil {
  		return false, err
  	}
  
  	return state == ThresholdActive, nil
  }
docs: // IsDeploymentActive returns true if the target deploymentID is active, and
  // false otherwise.
  //
  // This function is safe for concurrent access.