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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def _combine_document_events(new_event, old_events):
    ''' Attempt to combine a new event with a list of previous events.

    The ``old_event`` will be scanned in reverse, and ``.combine(new_event)``
    will be called on each. If a combination can be made, the function
    will return immediately. Otherwise, ``new_event`` will be appended to
    ``old_events``.

    Args:
        new_event (DocumentChangedEvent) :
            The new event to attempt to combine

        old_events (list[DocumentChangedEvent])
            A list of previous events to attempt to combine new_event with

            **This is an "out" parameter**. The values it contains will be
            modified in-place.

    Returns:
        None

    '''
    for event in reversed(old_events):
        if event.combine(new_event):
            return

    # no combination was possible
    old_events.append(new_event)