def legacy(wallet, hours: 24)
      raise 'You can\'t add legacy to a non-empty patch' unless @id.nil?
      wallet.txns.each do |txn|
        @txns << txn if txn.amount.negative? && txn.date < Time.now - hours * 60 * 60
      end
    end
def legacy(wallet, hours: 24)
      raise 'You can\'t add legacy to a non-empty patch' unless @id.nil?
      wallet.txns.each do |txn|
        @txns << txn if txn.amount.negative? && txn.date < Time.now - hours * 60 * 60
      end
    end
Add legacy transactions first, since they are negative and can't
 be deleted ever. This method is called by merge.rb in order to add
 legacy negative transactions to the patch before everything else. They
 are not supposed to be disputed, ever.