post
https://api.split.io/internal/api/v2/trafficTypes//environments//identities
Create or overwrite identities for a given traffic type in an FME environment. The attribute ID must start with a letter followed by a combination of dashes (-), underscores (_), letters (a-z A-Z), or numbers (0-9). Include the list of identities and their attributes to create or overwrite in the JSON body.