Prepare headers for http communication.

        Return dict of header to be used in requests.

        Args:
            .. versionadded:: 0.3.2
                **additional_headers**: (optional) Additional headers
                to be used with request

        Returns:
            Headers dict. Key and values are string

def _prepare_headers(self, additional_headers=None, **kwargs):
        """Prepare headers for http communication.

        Return dict of header to be used in requests.

        Args:
            .. versionadded:: 0.3.2
                **additional_headers**: (optional) Additional headers
                to be used with request

        Returns:
            Headers dict. Key and values are string

        """
        user_agent = "pyseaweed/{version}".format(version=__version__)
        headers = {"User-Agent": user_agent}
        if additional_headers is not None:
            headers.update(additional_headers)
        return headers