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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 edit_filename(filename, prefix='', suffix='', new_ext=None):
 """ Edit a file name by add a prefix, inserting a suffix in front of a file name extension or replacing the extension. Parameters filename : str The file name. prefix : str The prefix to be added. suffix : str The suffix to be inserted. new_ext : str, optional If not None, it replaces the original file name extension. Returns ------- new_filename : str The new file name. """

    base, ext = os.path.splitext(filename)

    if new_ext is None:
        new_filename = base + suffix + ext

    else:
        new_filename = base + suffix + new_ext

    return new_filename