def coerce(cls, string):
        """Create a :class:`Requirement` object from a given package spec."""
        match = re.match(cls.spec_regex, string)
        if not match:
            raise InvalidRequirementSpecError("could not parse requirement")
        package = match.group(1)
        if all(match.group(2, 3)):
            version = "".join(match.group(2, 3))
        else:
            version = None
        return cls(package, version)
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