public override string ToString()
{
var sb = new StringBuilder();
if (_map != null && _map.Count > 0)
{
foreach (Network network in _map)
{
sb.Append( network ).Append( ", " );
}
}
if (sb.ToString().EndsWith(", "))
sb.Length = sb.Length - 2;
if (sb.Length == 0)
sb.Append( "[No Nodes have been added]" );
return sb.ToString();
}