def batch_id(transaction_reference)
      grouped_transactions.each do |group, transactions|
        if transactions.select { |transaction| transaction.reference == transaction_reference }.any?
          return payment_information_identification(group)
        end
      end
    end
def batch_id(transaction_reference)
      grouped_transactions.each do |group, transactions|
        if transactions.select { |transaction| transaction.reference == transaction_reference }.any?
          return payment_information_identification(group)
        end
      end
    end
Returns the id of the batch to which the given transaction belongs
 Identified based upon the reference of the transaction