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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 _error_parse(self, interface, face):
 """ Parse the extensive xml output of an interface and yield errors. Purpose: Takes the xml output of 'show interfaces extensive' for a | given interface and yields the error types that have a | significant number of errors. @param interface: The xml output of the 'sh int ext' command for | the desired interface. @type interface: lxml.etree._Element object @param face: The direction of the errors we're wanting. Either 'input' | or 'output' is accepted. @type face: str @returns: Yields each error that has a significant number @rtype: iterable of strings. """

        try:
            error_list = interface.xpath(face + '-error-list')[0].getchildren()
        except IndexError:  # no error list on this interface
            pass
        else:
            for x in range(len(error_list)):
                if error_list[x].tag == "carrier-transitions":
                    if int(error_list[x].text.strip()) > 50:
                        yield " has greater than 50 flaps."
                elif int(error_list[x].text.strip()) > 0:
                    yield " has %s of %s." % (error_list[x].text.strip(),
                                              error_list[x].tag.strip())