public uint AddBorder(XMLBorderModel model)
 {
     return(_borders.Add(model));
 }
 public uint AddFill(XMLFillModel model)
 {
     return(_fills.Add(model));
 }
 public uint AddNumberFormat(string format)
 {
     return(_numberFormats.Add(format));
 }
 public uint AddFont(XMLFontModel model)
 {
     return(_fonts.Add(model));
 }
 public uint CommitStyle(XMLStyleModel style)
 {
     style.Index = _styles.Add(style);
     return(style.Index);
 }