System.Collections.ArrayList.Range.AddRange C# (CSharp) Method

            public override void AddRange(ICollection c)
            {
                if (c == null)
                {
                    throw new ArgumentNullException(nameof(c));
                }
                Contract.EndContractBlock();

                InternalUpdateRange();
                int count = c.Count;
                if (count > 0)
                {
                    _baseList.InsertRange(_baseIndex + _baseSize, c);
                    InternalUpdateVersion();
                    _baseSize += count;
                }
            }