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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_etree_root(doc, encoding=None):
 """Returns an instance of lxml.etree._Element for the given `doc` input. Args: doc: The input XML document. Can be an instance of ``lxml.etree._Element``, ``lxml.etree._ElementTree``, a file-like object, or a string filename. encoding: The character encoding of `doc`. If ``None``, an attempt will be made to determine the character encoding by the XML parser. Returns: An ``lxml.etree._Element`` instance for `doc`. Raises: IOError: If `doc` cannot be found. lxml.ParseError: If `doc` is a malformed XML document. """

    tree = get_etree(doc, encoding)
    root = tree.getroot()

    return root