'Show help for a particular authentication type.'

def opt_help_auth_type(self, authType):

    try:
        cf = findCheckerFactory(authType)
    except InvalidAuthType:
        raise usage.UsageError(('Invalid    auth    type:    %s' % authType))
    self.authOutput.write(('Usage:    --auth    %s[:ArgString]\n' % authType))
    self.authOutput.write(('ArgString    format:    %s\n' % cf.argStringFormat))
    self.authOutput.write('\n')
    for line in cf.authHelp.strip().splitlines():
        self.authOutput.write(('        %s\n' % line.rstrip()))
    self.authOutput.write('\n')
    if (not self.supportsCheckerFactory(cf)):
        self.authOutput.write(('        %s\n' % notSupportedWarning))
        self.authOutput.write('\n')
    raise SystemExit(0)
