Error Message:
201   System.ArgumentException : An item with the same key has already been added. Key: exampleKey
202  Stack Trace:
203     at System.Collections.Generic.Dictionary`2.TryInsert(TKey key, TValue value, InsertionBehavior behavior)
204   at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value)
205   at System.CommandLine.DictionaryExtensions.TryAdd[TKey,TValue](IDictionary`2 source, TKey key, TValue value)
206   at System.CommandLine.Collections.AliasedSet`1.Add(T item)
207   at System.CommandLine.Collections.SymbolSet.AddWithoutAliasCollisionCheck(ISymbol item)
208   at System.CommandLine.Symbol.AddParent(Symbol symbol)
209   at System.CommandLine.Command.AddSymbol(Symbol symbol)
210   at System.CommandLine.Command.Add(Symbol symbol)

internal static class DictionaryExtensions
    {
        public static TValue GetOrAdd<TKey, TValue>(
            this IDictionary<TKey, TValue> source,
            TKey key,
            Func<TKey, TValue> create)
        {
            lock (source)
            {
                if (source.TryGetValue(key, out TValue value))
                {
                   return value;
                }
                else
               {
                   value = create(key);
 
                   source.Add(key, value);
 
                  return value;
            }            
        }

        public static bool TryAdd<TKey, TValue>(
            this IDictionary<TKey, TValue> source,
            TKey key,
            TValue value)
        {
            lock (source)
            {
               if (source.ContainsKey(key))
               {
                  return false;
               }
               else
               {
                  source.Add(key, value);
                  return true;
               }
            }
        }
    }