Validation/AssertAzPresent.ps1

function AssertAzPresent()
{
    $azCmd = Get-Command az -ErrorAction SilentlyContinue
    if (-not $azCmd)
    {
        throw "The 'az' Azure CLI command is not found. Please go to https://docs.microsoft.com/en-us/cli/azure/install-azure-cli to install it."
    }
}