Tai.VenueAdapters.Bitmex.CreateOrder.to_venue_credentials

You're seeing just the function to_venue_credentials, go back to Tai.VenueAdapters.Bitmex.CreateOrder module for more information.
Link to this function

to_venue_credentials(credentials)

See Tai.VenueAdapters.Bitmex.Credentials.from/1.