Public/Get-OperatingSystem.ps1

function Get-OperatingSystem {
   [CmdletBinding()]
   param()

   if (_isOnWindows) {
      Write-Output 'Windows'
   }
   elseif (_isOnMac) {
      Write-Output 'macOS'
   }
   else {
      Write-Output 'Linux'
   }
}

Set-Alias WhereAmI Get-OperatingSystem
Set-Alias wai Get-OperatingSystem