Antlr4.Runtime.Misc.IntervalSet.AddAll C# (CSharp) Method

        public virtual Antlr4.Runtime.Misc.IntervalSet AddAll(IIntSet set)
        {
            if (set == null)
            {
                return this;
            }
            if (set is Antlr4.Runtime.Misc.IntervalSet)
            {
                Antlr4.Runtime.Misc.IntervalSet other = (Antlr4.Runtime.Misc.IntervalSet)set;
                // walk set and add each interval
                int n = other.intervals.Count;
                for (int i = 0; i < n; i++)
                {
                    Interval I = other.intervals[i];
                    this.Add(I.a, I.b);
                }
            }
            else
            {
                foreach (int value in set.ToList())
                {
                    Add(value);
                }
            }
            return this;
        }

 public virtual Antlr4.Runtime.Misc.IntervalSet Or(IIntSet a)
 {
     Antlr4.Runtime.Misc.IntervalSet o = new Antlr4.Runtime.Misc.IntervalSet();
     o.AddAll(this);
     o.AddAll(a);
     return(o);
 }