code: func NewDockerClientFromConfig(config *ClientConfig) libdocker.Interface {
  	if config != nil {
  		// Create docker client.
  		client := libdocker.ConnectToDockerOrDie(
  			config.DockerEndpoint,
  			config.RuntimeRequestTimeout,
  			config.ImagePullProgressDeadline,
  			config.WithTraceDisabled,
  			config.EnableSleep,
  		)
  		return client
  	}
  
  	return nil
  }
docs: // NewDockerClientFromConfig create a docker client from given configure
  // return nil if nil configure is given.