private static async Task <Permission> CreatePermission(IDocumentClient client, User user, string permId, PermissionMode permissionMode, string resourceLink)
        {
            Console.WriteLine($">>> Create Permission {permId} for {user.Id} <<<");

            Permission permissionDefinition = new Permission {
                Id = permId, PermissionMode = permissionMode, ResourceLink = resourceLink
            };
            ResourceResponse <Permission> result = await client.CreatePermissionAsync(user.SelfLink, permissionDefinition);

            Permission permission = result.Resource;

            Console.WriteLine("Created new permission");
            PrintPermission(permission);

            return(permission);
        }