public bool Contains (SchemaImporterExtension extension)
		{
			if (extension == null)
				throw new ArgumentNullException ("extension");
			foreach (SchemaImporterExtension e in List)
				if (extension.Equals (e))
					return true;
			return false;
		}
        public int IndexOf(SchemaImporterExtension extension)
        {
            if (extension == null)
            {
                throw new ArgumentNullException("extension");
            }
            int i = 0;

            foreach (SchemaImporterExtension e in List)
            {
                if (extension.Equals(e))
                {
                    return(i);
                }
                i++;
            }
            return(-1);
        }
		public int IndexOf (SchemaImporterExtension extension)
		{
			if (extension == null)
				throw new ArgumentNullException ("extension");
			int i = 0;
			foreach (SchemaImporterExtension e in List) {
				if (extension.Equals (e)) {
					return i;
				}
				i++;
			}
			return -1;
		}