To add data to a Datastream
        :param datastream: string
        :param data_type: string
        :param options: dict
        :param data: string

def add_input_data(self, datastream, data_type, options, data):
        """
        To add data to a Datastream
        :param datastream: string
        :param data_type: string
        :param options: dict
        :param data: string
        """

        url = self.get_add_input_data_url(datastream, options)

        form_data = {
            'files': {
                'data': (
                    Utils.random_string(10)+('.json' if data_type == 'json' else '.csv'),
                    StringIO(data),
                    'text/plain;charset=UTF-8',
                    {'Expires': '0'}
                )
            }
        }
        response = self.http.fpost(url, form_data)
        return response