code: import stripe
  stripe.api_key = "sk_test_your_key"
  
  stripe.Invoice.upcoming(
    customer='cus_8TEMHVY5moxIPI',
  )
  '''Response {
    "object": "invoice",
    "account_country": "US",
    "account_name": "Stripe.com",
    "account_tax_ids": null,
    "amount_due": 300,
    "amount_paid": 0,
    "amount_remaining": 300,
    "application": null,
    "application_fee_amount": null,
    "attempt_count": 0,
    "attempted": false,
    "automatic_tax": {
      "enabled": false,
      "status": null
    },
    "billing_reason": "manual",
    "charge": null,
    "collection_method": "charge_automatically",
    "created": 1659518855,
    "currency": "usd",
    "custom_fields": null,
    "customer": "cus_8TEMHVY5moxIPI",
    "customer_address": null,
    "customer_email": "ava.anderson.22@example.com",
    "customer_name": null,
    "customer_phone": null,
    "customer_shipping": null,
    "customer_tax_exempt": "none",
    "customer_tax_ids": [],
    "default_payment_method": null,
    "default_source": null,
    "default_tax_rates": [],
    "description": null,
    "discount": null,
    "discounts": [],
    "due_date": null,
    "ending_balance": null,
    "footer": null,
    "last_finalization_error": null,
    "lines": {
      "object": "list",
      "data": [
        {
          "id": "il_1LSdrX2eZvKYlo2CwVfODzHa",
          "object": "line_item",
          "amount": 300,
          "amount_excluding_tax": 300,
          "currency": "usd",
          "description": "My First Invoice Item (created for API docs)",
          "discount_amounts": [],
          "discountable": true,
          "discounts": [],
          "invoice_item": "ii_1LSdrX2eZvKYlo2Crz8rasOM",
          "livemode": false,
          "metadata": {},
          "period": {
            "end": 1659518855,
            "start": 1659518855
          },
          "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,
          "proration_details": {
            "credited_items": null
          },
          "quantity": 1,
          "subscription": null,
          "tax_amounts": [],
          "tax_rates": [],
          "type": "invoiceitem",
          "unit_amount_excluding_tax": "300"
        }
      ],
      "has_more": false,
      "url": "/v1/invoices/upcoming/lines?customer=cu_18CHts2eZvKYlo2CbmAAQORe"
    },
    "livemode": false,
    "metadata": {},
    "next_payment_attempt": null,
    "number": null,
    "on_behalf_of": null,
    "paid": false,
    "paid_out_of_band": false,
    "payment_intent": null,
    "payment_settings": {
      "default_mandate": null,
      "payment_method_options": null,
      "payment_method_types": null
    },
    "period_end": 1659518855,
    "period_start": 1659518855,
    "post_payment_credit_notes_amount": 0,
    "pre_payment_credit_notes_amount": 0,
    "quote": null,
    "receipt_number": null,
    "redaction": null,
    "rendering_options": null,
    "starting_balance": 0,
    "statement_descriptor": null,
    "status": "draft",
    "status_transitions": {
      "finalized_at": null,
      "marked_uncollectible_at": null,
      "paid_at": null,
      "voided_at": null
    },
    "subscription": null,
    "subtotal": 300,
    "subtotal_excluding_tax": 300,
    "tax": null,
    "test_clock": null,
    "total": 300,
    "total_discount_amounts": [],
    "total_excluding_tax": 300,
    "total_tax_amounts": [],
    "transfer_data": null,
    "webhooks_delivered_at": null
  }'''
nl: Retrieve an upcoming invoiceAt any time, you can preview the upcoming invoice for a customer. This will show you all the charges that are pending, including subscription renewal charges, invoice item charges, etc. It will also show you any discounts that are applicable to the invoice.
  Note that when you are viewing an upcoming invoice, you are simply viewing a preview – the invoice has not yet been created. As such, the upcoming invoice will not show up in invoice listing calls, and you cannot use the API to pay or edit the invoice. If you want to change the amount that your customer will be billed, you can add, remove, or update pending invoice items, or update the customer’s discount.
  You can preview the effects of updating a subscription, including a preview of what proration will take place. To ensure that the actual proration is calculated exactly the same as the previewed proration, you should pass a proration_date parameter when doing the actual subscription update. The value passed in should be the same as the subscription_proration_date returned on the upcoming invoice resource. The recommended way to get only the prorations being previewed is to consider only proration line items where period[start] is equal to the subscription_proration_date on the upcoming invoice resource.Parameters customer Required if subscription unset The identifier of the customer whose upcoming invoice you’d like to retrieve. subscription optional The identifier of the subscription for which you’d like to retrieve the upcoming invoice. If not provided, but a subscription_items is provided, you will preview creating a subscription with those items. If neither subscription nor subscription_items is provided, you will retrieve the next upcoming invoice from among the customer’s subscriptions.More parametersExpand all  customer_details Required if subscription and customer unset   automatic_tax optional dictionary   coupon optional   currency optional   discounts optional array of hashes   invoice_items optional array of hashes   schedule optional   subscription_billing_cycle_anchor optional   subscription_cancel_at optional   subscription_cancel_at_period_end optional   subscription_cancel_now optional   subscription_default_tax_rates optional   subscription_items optional array of hashes   subscription_proration_behavior optional   subscription_proration_date optional   subscription_start_date optional   subscription_trial_end optional   subscription_trial_from_plan optional ReturnsReturns an invoice if valid customer information is provided. Raises an error otherwise