Explanation:
payload
Used to define the body of the RESTCONF request. This variable holds the VLAN configuration that will be sent.
post
Specifies the HTTP method to create new resources on the device. VLAN creation requires a POST request.
auth
Provides basic authentication credentials (username and password) required by the RESTCONF server.
data
Assigns the request body. The payload variable is passed to the data parameter of the requests.post() method.