def mailbox(self):
path = '<STR_LIT>'<EOL>response_data = self.request(path)<EOL>return response_data<EOL>
Get a dictionary containing email addresses of people who have received messages from the sandbox
http://docs.fiesta.cc/sandbox.html#get--mailbox

Structured like this:
    {
      mike@corp.fiesta.cc: [
        {
          text: "Hello world.",
          subject: "Saying hello"
        },
        ...
      ],
      ...
    }