Return read-only copy of this object

		:return: WHTTPHeaders

def ro(self):
		""" Return read-only copy of this object

		:return: WHTTPHeaders
		"""
		ro_headers = WHTTPHeaders()
		names = self.headers()
		for name in names:
			ro_headers.add_headers(name, *self.get_headers(name))
		ro_headers.__cookies = self.__set_cookies.ro()
		ro_headers.__ro_flag = True
		return ro_headers