make it possible in the "send" method to transfer files in base64 (as in the API specification)

[ruslans-zkz]

I already have a base64 encoded file as a string, but I cannot send it because the "send" method expects me to provide an unencoded list of files. Now, for my code to work, I must first decode base64, then wrap it in BytesIO, and only then pass it to the "send" method.