private void SetUpdatableFlag(Package package)
{
var latest = _packages.SingleOrDefault(n => n.Id == package.Id && n.Flags.All(m => m != "installed") && n.Flags.Any(m => m == "latest"));
if (latest != null)
{
package.AddFlags("updatable");
}
else
{
package.RemoveFlags("updatable");
}
}