Add checkbox logic to lists and groups.
Fixed bug with old_email
Corrected endpoint link.
Fixed bug to ensure custom_fields are updated on unsubscribe.
Ensure a list can't be selected more than once for a particular class.
Refactor logic so webhook stops running if no custom_field related to the list_id exists.
Added validation to ensure mailchimp_list fields are only added to classes that contain an 'email' attribute.
Whitespace