code: func SetDefaultNetModeIfBlank(hc *container.HostConfig) {
  	if hc != nil {
  		if hc.NetworkMode == container.NetworkMode("") {
  			hc.NetworkMode = container.NetworkMode("default")
  		}
  	}
  }
docs: // SetDefaultNetModeIfBlank changes the NetworkMode in a HostConfig structure
  // to default if it is not populated. This ensures backwards compatibility after
  // the validation of the network mode was moved from the docker CLI to the
  // docker daemon.