code: public function seek($column = 'A')
      {
          $column = Coordinate::columnIndexFromString($column);
          if (($column < $this->startColumnIndex) || ($column > $this->endColumnIndex)) {
              throw new PhpSpreadsheetException("Column $column is out of range ({$this->startColumnIndex} - {$this->endColumnIndex})");
          }
          $this->currentColumnIndex = $column;
  
          return $this;
      }
docs: Set the column pointer to the selected column.
  
  @param string $column The column address to set the current pointer at
  
  @throws PhpSpreadsheetException
  
  @return ColumnIterator