<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _create_dom(data):
 """ Creates doublelinked DOM from `data`. Args: data (str/HTMLElement):
 Either string or HTML element. Returns: obj: HTMLElement containing double linked DOM. """

    if not isinstance(data, dhtmlparser.HTMLElement):
        data = dhtmlparser.parseString(
            utils.handle_encodnig(data)
        )

    dhtmlparser.makeDoubleLinked(data)

    return data