Executes an operational show-type command.

def _execute_show(self, show_command):
        """
        Executes an operational show-type command.
        """
        rpc_command = '<CLI><Exec>{show_command}</Exec></CLI>'.format(
            show_command=escape_xml(show_command)
        )
        response = self._execute_rpc(rpc_command)
        raw_response = response.xpath('.//CLI/Exec')[0].text
        return raw_response.strip() if raw_response else ''