func Get(name string) (Provisioner, error) {
	pFunc, ok := provisioners[name]
	if !ok {
		return nil, errors.Errorf("unknown provisioner: %q", name)
	}
	return pFunc()
}
func Get(name string) (Provisioner, error) {
	pFunc, ok := provisioners[name]
	if !ok {
		return nil, errors.Errorf("unknown provisioner: %q", name)
	}
	return pFunc()
}
// Get gets the named provisioner from the registry.