How to get open api line number in custom function

[JGPrakash]

If I run the spectral lint command with the core function, it returns the warning message with which line number it has a problem.
Now I want to implement the same in a custom function.

for example
openapi:

info:
  description: This is a simple API
  version: "1.0.0"
  title: Simple Inventory API 

Ruleset:

then: {
function: casing,
functionOptions: {
type: camel
},
},
Output:

 9:10  warning  casing-ruleset  must be camel case  info.title

✖ 1 problem (0 errors, 1 warning, 0 infos, 0 hints)

The title is present in line number 9 in the open API.
In the same way, I want to display the message in a custom function.
How to display the open API line number in custom functions?