We need new data types and structures to describe a transaction in a standardized format:
      ⚙️ Terms (optional):
      
    - one-time or recurring transactions
- shipping (to, from, terms)
- payment (method, terms, received?)
- warranty
- cancellation
      💸 Money:
      
    - Currency (ISO 4217 standard), crypto currency ticker
- Amount (in nominal unit and – optionally – minor unit)
      🕐 Datetime:
      
  - on
- before
- until
- after