WHMAPI1 Addpkgext Package Extensions Key Value (cPanel)

I am trying to run this WHMAPI1 command using the shell to add package extensions to a package using the guide https://api.docs.cpanel.net/openapi/whm/operation/addpkgext/

We have created 3 Package extensions and working well on the WHM interface, but we need to activate these extensions from WHMAPI calls.

The command we are using is :

whmapi1 addpkgext name=samplepackage _PACKAGE_EXTENSIONS='ext1=value ext2=value ext3=value'

On the guide, it clearly says we can use Key=Value pairs in the command but when we run the above command, it returns -

metadata:
  command: addpkgext
  reason: Package extension value is invalid.
  result: 0
  version: 1

I am getting the same result when I use "addpkg", "editpkd", or "modifypkg" API functions.

Can anyone help me sort this?

Thanks!