def remove(self, elem):
        """Remove a requirement.

        :param elem: a string or :class:`Requirement` instance.
        """
        if isinstance(elem, text_type):
            for requirement in self:
                if requirement.package == elem:
                    return super(Requirements, self).remove(requirement)
        return super(Requirements, self).remove(elem)
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