---
title: "Comment by David Novák on \"Practical Guide to Fp-ts P5: Apply, Sequences, and Traversals\" | Hashnode"
description: "The problem with this code: sequenceS(E.either)({ email: validateEmail(email), password: validatePassword(password), }) Is if validateEmail and validatePassword"
url: "https://hashnode.com/posts/practical-guide-to-fp-ts-part-5/6071bd511494367be6d29fcf/comment/642be27c39fb0f053a106729"
---

[Discussion](https://hashnode.com/posts/practical-guide-to-fp-ts-part-5/6071bd511494367be6d29fcf)

Comment [Practical Guide to Fp-ts P5: Apply, Sequences, and Traversals](https://hashnode.com/posts/practical-guide-to-fp-ts-part-5/6071bd511494367be6d29fcf)

[David Novák](https://hashnode.com/@kaladivo)

[Apr 4, 2023](https://hashnode.com/posts/practical-guide-to-fp-ts-part-5/6071bd511494367be6d29fcf/comment/642be27c39fb0f053a106729)

The problem with this code:

sequenceS(E.either)({ email: validateEmail(email), password: validatePassword(password), })

Is if validateEmail and validatePassword has different left types it wont compile.

Is there a way around this?