unLink method

void unLink(
  1. String sheet
)

If sheet is linked with any other sheet's object then it's link will be broke

Implementation

void unLink(String sheet) {
  if (_sheetMap[sheet] != null) {
    ///
    /// copying the sheet into itself thus resulting in breaking the linkage as Sheet._clone() will provide new reference;
    copy(sheet, sheet);
  }
}