what is gazebo_msgs/ModelStates dependencies? [closed]

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I tried to use gazebo_msgs::ModelStates but it does not compile. When I use gazebo_msgs::ModelState I will get the error below:

[ERROR] [1430752035.526287969, 184.707000000]: Client [/listener] wants topic /gazebo/model_states to have datatype/md5sum [gazebo_msgs/ModelState/9330fd35f2fcd82d457e54bd54e10593], but our version has [gazebo_msgs/ModelStates/48c080191eb15c41858319b4d8a609c2]. Dropping connection.

Here is my code, what should I include for using gazebo_msgs/ModelStates?

  #include "ros/ros.h"
  #include "std_msgs/String.h"
  #include "gazebo_msgs/ModelStates.h"

  void chatterCallback(const gazebo_msgs::ModelStates::ConstPtr& msg)
  { 
     ROS_INFO("I heard: ");
  }

int main(int argc, char **argv)
{
  ros::init(argc, argv, "listener");
  ros::NodeHandle n;
  ros::Subscriber sub = n.subscribe("/gazebo/model_states", 1000, chatterCallback);
  ros::spin();
}