'Write all errors and callers to the XML output file.
:return: None, we write the data to the XML'

def _write_errors_to_xml(self):

    for (message, caller) in self._errors:
        message_node = self._xml.createElement('error')
        message_node.setAttribute('caller', xml_str(caller))
        description = self._xml.createTextNode(xml_str(message))
        message_node.appendChild(description)
        self._top_elem.appendChild(message_node)
