public ChangeLogDefinition <TState> And(ChangeLogDefinition <TState> definition)
{
foreach (var pair in definition._handle)
{
var eventType = pair.Key;
var handler = pair.Value;
if (_handle.ContainsKey(eventType))
{
throw new HandlerIsAlreadyDefinedException(eventType);
}
_handle[eventType] = handler;
}
return(this);
}