Add support for signing groups

[rajmoodaley]

Please add support for this feature in the API that was release 1 year ago

Allows a sender to send a signature request to a group of individuals any of whom can claim and sign the signature request.

[janetanne]

Thanks @rajmoodaley, we will look into this.

For now, you should be able to create a raw HTTP request using a requests library in order to use the parameter. I'll look into this and create a code sample for you.