/// <summary>
/// Parses the key/value pair from a node, and adds them to the result.
/// </summary>
/// <param name="elem">Element to get info from.</param>
/// <param name="res">Result object to extract data to.</param>
private void AddDataToResult(IDomElement elem, OpenGraphData res)
{
var key = ParseKeyFromNode(elem);
if (!res.ContainsKey(key))
{
res.Add(key, ParseValueFromNode(elem));
}
}
