returns the JSON object
        {'embedded': {
          'sign_url': 'https://www.hellosign.com/editor/embeddedSign?signature_id={signature_id}&token={token}',
          'expires_at': {timestamp}
        }}

def create(self, **kwargs):
        """
        returns the JSON object
        {'embedded': {
          'sign_url': 'https://www.hellosign.com/editor/embeddedSign?signature_id={signature_id}&token={token}',
          'expires_at': {timestamp}
        }}        
        """
        auth = None
        if 'auth' in kwargs:
            auth = kwargs['auth']
            del(kwargs['auth'])

        self._url = '%s%s%s' % (self.base_uri, 'embedded/sign_url/', self.signature_id)

        return self.embedded.sign_url.get(auth=auth, **kwargs)