/// <summary>
        /// Removes the sub field.
        /// </summary>
        /// <param name="code">The code.</param>
        /// <returns></returns>
        /// <remarks>Удаляет все повторения подполей
        /// с указанным кодом.
        /// </remarks>
        public RecordField RemoveSubField
        (
            char code
        )
        {
            code = char.ToLowerInvariant(code);
            SubField[] found = SubFields
                               .FindAll(_ => char.ToLowerInvariant(_.Code) == code)
                               .ToArray();

            foreach (SubField subField in found)
            {
                SubFields.Remove(subField);
            }

            return(this);
        }