def _traverse(summary, function, *args):
    """Traverse all objects of a summary and call function with each as a
    parameter.

    Using this function, the following objects will be traversed:
    - the summary
    - each row
    - each item of a row
    """
    function(summary, *args)
    for row in summary:
        function(row, *args)
        for item in row:
            function(item, *args)