}
final CellReference startCell = new CellReference( cellRef[0] );
final CellReference endCell = new CellReference( cellRef[1] );
final CTTableColumns columns = sht.getTableColumns();
assert columns!=null;
assert columns.getCount()>0;
if( columns==null || columns.getCount()<=0 ) {
final String msg = String.format( "non columns detected!" );
log.error( msg);
throw new IllegalStateException(msg);
}
// FOR EACH COLUMN
for( int col =0 ; col< columns.getCount(); ++col ) {
final CTTableColumn tableCol = columns.getTableColumnArray(col);
assert tableCol!=null;
if( tableCol==null ) {
final String msg = String.format( "column [%d] is null. Will be ignored ", col );
log.warn( msg);