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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 _get_file_name(tlobject):
 """``ClassName -> class_name.html``."""

    name = tlobject.name if isinstance(tlobject, TLObject) else tlobject
    # Courtesy of http://stackoverflow.com/a/1176023/4759433
    s1 = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', name)
    result = re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1).lower()
    return '{}.html'.format(result)