requireSession :: Text -> Text -> Handler Text
requireSession pam errstr = lookupSession pam >>= \mv -> case mv of
    Nothing -> invalidArgsI [errstr]
    Just v  -> return v
requireSession :: Text -> Text -> Handler Text
requireSession pam errstr = lookupSession pam >>= \mv -> case mv of
    Nothing -> invalidArgsI [errstr]
    Just v  -> return v
requireSession pam errstr = lookupSession pam >>= \mv -> case mv of
    Nothing -> invalidArgsI [errstr]
    Just v  -> return v