responseBody: {
  anyOf: [
    { // 200 response:
      type: 'object',
      required: ['refundAmountsByPaymentSource'],
      properties: {
        refundAmountsByPaymentSource: {
          type: 'object',
          minProperties: 1,
          additionalProperties: false,
          properties: {
            stripe: {
              type: 'number',
              min: 0.01,
            },
            userStoreCredit: {
              type: 'number',
              min: 0.01,
            },
            goodEggsPromo: {
              type: 'number',
              min: 0.01,
            },
          },
        },
      },
    },
    { // 404 response:
      type: 'object',
      // ???
    },
    { // 400 response:
      type: 'object',
      required: ['error'],
      properties: {
        error: {
          type: 'object',
          required: ['type'],
          properties: {
            type: {
              type: 'string',
              enum: [
                'PARAMETER_REQUIRED',
                'INVOICE_NOT_FOUND',
                'NOT_ENOUGH_LINE_ITEMS',
                'AMOUNT_NOT_IN_RANGE',
              ],
            },
          },
        },
      },
    },
  ],
},