'Enter enable mode'

def enable(self, cmd=u'enable', pattern=u'password', re_flags=re.IGNORECASE, default_username=u'manager'):

    output = self.send_command_timing(cmd)
    if (u'username' in output.lower()):
        output += self.send_command_timing(default_username)
    if (u'password' in output.lower()):
        output += self.send_command_timing(self.secret)
    log.debug(u'{0}'.format(output))
    self.clear_buffer()
    return output
