def add_custom_variables(reco_event,truth_event):
    """
        Example of adding custom variables to the csv - this is a dummy and returns the value of
        1.0 and the eventNumber twice for every event. 

        The objects passed to this function are the root2csv two TTrees. 

        This function MUST return an array 
    """
    return [1.0,reco_event.eventNumber,truth_event.eventNumber]