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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 _reinsert_root_tag_prefix(v):
 """ Returns namespace prefix to root tag, if it had one. """

    if hasattr(v, 'original_prefix'):
        original_prefix = v.original_prefix
        del v.original_prefix
        v.tag = ''.join(('{', v.nsmap[original_prefix], '}VOEvent'))
    return