code: public OvhVolume project_serviceName_volume_volumeId_attach_POST(String serviceName, String volumeId, String instanceId) throws IOException {
  		String qPath = "/cloud/project/{serviceName}/volume/{volumeId}/attach";
  		StringBuilder sb = path(qPath, serviceName, volumeId);
  		HashMap<String, Object>o = new HashMap<String, Object>();
  		addBody(o, "instanceId", instanceId);
  		String resp = exec(qPath, "POST", sb.toString(), o);
  		return convertTo(resp, OvhVolume.class);
  	}
docs: Attach a volume on an instance
  
  REST: POST /cloud/project/{serviceName}/volume/{volumeId}/attach
  @param instanceId [required] Instance id
  @param serviceName [required] Service name
  @param volumeId [required] Volume id