System.Security.Claims.ClaimsIdentity.SafeAddClaim C# (CSharp) Method

        private void SafeAddClaim(Claim claim)
        {
            if (claim == null)
                return;

            if (object.ReferenceEquals(claim.Subject, this))
            {
                _instanceClaims.Add(claim);
            }
            else
            {
                _instanceClaims.Add(claim.Clone(this));
            }
        }