LitJson with a json that does not always contain a field

KeyNotFoundException: The given key was not present in the dictionary.
System.Collections.Generic.Dictionary`2[System.String,LitJson.JsonData].get_Item (System.String key) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.Collections.Generic/Dictionary.cs:150)

I’m using litjson in unity to parse data from steam api. The json field that I want from steam is only returned when I am in game. Otherwise the field isnt posted in the json output. I need to use this field but it crashes with the above error when I dont have a game running. Any chance anyone has a work around for this?

using UnityEngine;
using System.Collections;
using LitJson;

public class JsonFetcher : MonoBehaviour {

	public string url; 
	private JsonData _JsonData;
	private string sPlayerAPIHeader = "FAKEHTTP";
	//private string sGamersGambitFriendList = "FAKEHTTP";
	// Use this for initialization
	IEnumerator Start(){
		
		WWW steamData = new WWW(sPlayerAPIHeader);
		yield return steamData;
		string steamDataStr = steamData.text;    		
		_JsonData = JsonMapper.ToObject (steamDataStr);
		string _Json = (string)_JsonData["response"]["players"][0]["gameid"];
		Debug.Log (_Json);
		Destroy (gameObject);

	}
	
	// Update is called once per frame
	void Update () {
		//
	}

}

Well I found my own solution so I thought I would post it here for others to reference.

WWW steamData = new WWW(sPlayerAPIHeader);
		yield return steamData;
		string steamDataStr = steamData.text;
		_JsonData = JsonMapper.ToObject (steamDataStr);
		if (steamData.text.Contains ("gameid")) {
			string _Json = (string)_JsonData ["response"] ["players"] [0] ["gameid"];
			Debug.Log (_Json);
			Destroy (gameObject);
		} else {
			Debug.Log ("Not in game");
		}

	}