Disco.Services.Interop.ActiveDirectory.ActiveDirectoryGroupCache.TryDistinguishedNameCache C# (CSharp) Method

        private Tuple<ADGroup, DateTime> TryDistinguishedNameCache(string DistinguishedName)
        {
            Tuple<ADGroup, DateTime> groupRecord;
            if (distinguishedNameCache.TryGetValue(DistinguishedName, out groupRecord))
            {
                if (groupRecord.Item2 > DateTime.Now)
                    return groupRecord;
                else
                {
                    if (distinguishedNameCache.TryRemove(DistinguishedName, out groupRecord))
                        securityIdentifierCache.TryRemove(groupRecord.Item1.SecurityIdentifier, out groupRecord);
                }
            }
            return null;
        }
        private Tuple<ADGroup, DateTime> TrySecurityIdentifierCache(SecurityIdentifier SecurityIdentifier)