Sets multiple headers on the request and returns the request itself.

        Keyword arguments:
        headers -- a dict-like object which contains the headers to set.

def with_headers(self, headers):
        """Sets multiple headers on the request and returns the request itself.

        Keyword arguments:
        headers -- a dict-like object which contains the headers to set.
        """
        for key, value in headers.items():
            self.with_header(key, value)
        return self