public bool IsDeviceCodeGrantApproved(string deviceCode)
        {
            DeviceCodeGrant grant = DeviceGrants.FirstOrDefault(x => x.DeviceCode == deviceCode);

            if (grant is null)
            {
                throw new Exception($"Invalid device code '{deviceCode}'");
            }

            return(grant.Approved);
        }
        public void ApproveDeviceCodeGrant(string userCode)
        {
            DeviceCodeGrant grant = DeviceGrants.FirstOrDefault(x => x.UserCode == userCode);

            if (grant is null)
            {
                throw new Exception($"Invalid user code '{userCode}'");
            }

            grant.Approved = true;
        }