Minor fix

Author: eyw520

doc/api/refunds.md

@@ -45,7 +45,7 @@ def list_payment_refunds(self,
 |  --- | --- | --- | --- |
 | `begin_time` | `str` | Query, Optional | Indicates the start of the time range to retrieve each `PaymentRefund` for, in RFC 3339<br>format.  The range is determined using the `created_at` field for each `PaymentRefund`.<br><br>Default: The current time minus one year. |
 | `end_time` | `str` | Query, Optional | Indicates the end of the time range to retrieve each `PaymentRefund` for, in RFC 3339<br>format.  The range is determined using the `created_at` field for each `PaymentRefund`.<br><br>Default: The current time. |
-| `updated_at_begin_time` | `string` | Query, Optional | Indicates the start of the time range to retrieve each `PaymentRefund` for, in RFC 3339<br>format.  The range is determined using the `updated_at` field for each `PaymentRefund`.<br><br>Default: if omitted, the time range starts at `beginTime`. |
+| `updated_at_begin_time` | `string` | Query, Optional | Indicates the start of the time range to retrieve each `PaymentRefund` for, in RFC 3339<br>format.  The range is determined using the `updated_at` field for each `PaymentRefund`.<br><br>Default: if omitted, the time range starts at `begin_time`. |
 | `updated_at_end_time` | `string` | Query, Optional | Indicates the end of the time range to retrieve each `PaymentRefund` for, in RFC 3339<br>format.  The range is determined using the `updated_at` field for each `PaymentRefund`.<br><br>Default: The current time. |
 | `sort_field` | `string` | Query, Optional | The field used to sort results by. The default is `CREATED_AT`.<br>Current values include `CREATED_AT` and `UPDATED_AT`.<br> |
 | `sort_order` | `str` | Query, Optional | The order in which results are listed by `PaymentRefund.created_at`:<br><br>- `ASC` - Oldest to newest.<br>- `DESC` - Newest to oldest (default). |