def load(self, filename, create_if_missing=True):
        filename = Path(filename)
        if not filename.exists() and create_if_missing:
            self.load_pip_requirements()
            with filename.open("w") as f:
                f.write(yaml.dump(self.serialized, default_flow_style=False,
                                  encoding=None))
            self.filename = filename
            return self.save(filename)
        with filename.open() as f:
            for group, requirements in yaml.load(f.read()).items():
                for requirement in requirements:
                    self[group].add(Requirement.coerce(requirement))
        self.filename = filename
async def handler(client, request):
		if request.path == "/v6/challenge":
			assert request.encode().decode() == CHALLENGE_REQUEST
			response = http.HTTPResponse(200)
			response.json = {
				"challenge": "vaNgVZZH7gUse0y3t8Cksuln-TAVtvBmcD-ow59qp0E=",
				"data": "dlL7ZBNSLmYo1hUlKYZiUA=="
			}
			return response
		else:
			assert request.encode().decode() == TOKEN_REQUEST
			response = http.HTTPResponse(200)
			response.json = {
				"device_auth_token": "device token"
			}
			return response