How to guess if an email is used by any user in a chat?



Working with API, before createing a new user for a chat, I want to know a way to guess if any of the existing users of the chat could already have the email of the new user ( for example).

I’m trying with users.list?query but it doesn’t seem to solve the problem, or I’m not using it fine.

Anyone who could help me?



If you try register it should return an error if email exists.