code: def to_etree(xml):
          
          if isinstance(xml, OneLogin_Saml2_XML._element_class):
              return xml
          if isinstance(xml, OneLogin_Saml2_XML._bytes_class):
              return OneLogin_Saml2_XML._parse_etree(xml, forbid_dtd=True)
          if isinstance(xml, OneLogin_Saml2_XML._text_class):
              return OneLogin_Saml2_XML._parse_etree(compat.to_bytes(xml), forbid_dtd=True)
  
          raise ValueError('unsupported type %r' % type(xml))
docs: Parses an XML document or fragment from a string.
          :param xml: the string to parse
          :type xml: str|bytes|xml.dom.minidom.Document|etree.Element
          :returns: the root node
          :rtype: OneLogin_Saml2_XML._element_class