Logs into the Cisco Coverage API in batches (up to 75 serial numbers per request), retrieves coverage data for Cisco devices by serial number, and updates the custom fields: support_end_of_coverage, support_end_of_warranty, and support_iscovered.
You need access to the Cisco Support API (SN2Info). See https://developer.cisco.com/docs/support-apis/serial-number-to-information/#introduction
Create three custom fields in NetBox:

Download the script and add CLIENT_ID and CLIENT_SECRET.
Upload the python script to netbox under Customization -> Scripts.
Run it.