class Mindee::Product::InvoiceSplitter::InvoiceSplitterV1InvoicePageGroups

def to_s
  return '' if empty?
  lines = map do |entry|
    "\n  #{entry.to_table_line}\n#{self.class.line_items_separator('-')}"
  end.join
  out_str = String.new
  out_str << "\n#{self.class.line_items_separator('-')}\n "
  out_str << ' | Page Indexes                                                            '
  out_str << " |\n#{self.class.line_items_separator('=')}"
  out_str + lines
end