code: import stripe
  stripe.api_key = "sk_test_your_key"
  
  stripe.InvoiceItem.modify(
    "ii_1LSe4Q2eZvKYlo2CYN9PE9sv",
    metadata={"order_id": "6735"},
  )
  '''Response {
    "id": "ii_1LSe4Q2eZvKYlo2CYN9PE9sv",
    "object": "invoiceitem",
    "amount": 300,
    "currency": "usd",
    "customer": "cus_8TEMHVY5moxIPI",
    "date": 1659519654,
    "description": "My First Invoice Item (created for API docs)",
    "discountable": true,
    "discounts": [],
    "invoice": null,
    "livemode": false,
    "metadata": {
      "order_id": "6735"
    },
    "period": {
      "end": 1659519654,
      "start": 1659519654
    },
    "price": {
      "id": "price_1LScCX2eZvKYlo2C1Z9zPyXF",
      "object": "price",
      "active": true,
      "billing_scheme": "per_unit",
      "created": 1659512469,
      "currency": "usd",
      "custom_unit_amount": null,
      "livemode": false,
      "lookup_key": null,
      "metadata": {},
      "nickname": null,
      "product": "prod_MAy8UvSA0uRRju",
      "recurring": null,
      "tax_behavior": "unspecified",
      "tiers_mode": null,
      "transform_quantity": null,
      "type": "one_time",
      "unit_amount": 300,
      "unit_amount_decimal": "300"
    },
    "proration": false,
    "quantity": 1,
    "subscription": null,
    "tax_rates": [],
    "test_clock": null,
    "unit_amount": 300,
    "unit_amount_decimal": "300"
  }'''
nl: Update an invoice itemUpdates the amount or description of an invoice item on an upcoming invoice. Updating an invoice item is only possible before the invoice it’s attached to is closed.Parameters amount optional The integer amount in cents of the charge to be applied to the upcoming invoice. If you want to apply a credit to the customer’s account, pass a negative amount. description optional An arbitrary string which you can attach to the invoice item. The description is displayed in the invoice for easy tracking. metadata optional dictionary Set of key-value pairs that you can attach to an object. This can be useful for storing additional information about the object in a structured format. Individual keys can be unset by posting an empty value to them. All keys can be unset by posting an empty value to metadata. period optional dictionary The period associated with this invoice item. When set to different values, the period will be rendered on the invoice.Show child parameters price optional The ID of the price object.More parametersExpand all  discountable optional   discounts optional array of hashes   price_data optional dictionary   quantity optional   tax_rates optional   unit_amount optional   unit_amount_decimal optional ReturnsThe updated invoice item object is returned upon success. Otherwise, this call raises an error