PaymentMethod

Payment method information for PayPal Cart API. This API is specifically designed for PayPal's shopping cart service, so only PayPal payment methods are supported.

Payment Flow:

1. Cart creation generates a payment token (in payment_method.token)
2. Customer completes PayPal approval (Smart Wallet)
3. PayPal provides token and payer_id for checkout
4. Merchant receives PayPal payment confirmation

Billing Address Behavior:

• PayPal handles all billing address collection internally for payment processing
• Merchants can optionally collect billing addresses for tax calculation and business purposes
• Billing address in cart is for merchant use cases, not payment requirements
• Billing addresses are typically available from customer profile data

Note: Other payment methods (credit cards, Apple Pay, etc.) would be handled by separate merchant payment systems outside of this PayPal Cart API.