daemon/graphdriver/plugin_unsupported.go - third_party/github.com/moby/moby - Git at Google

 // +build !experimental

 package graphdriver

 func lookupPlugin(name, home string, opts []string) (Driver, error) {
 	return nil, ErrNotSupported
 }
	// +build !experimental

	package graphdriver

	func lookupPlugin(name, home string, opts []string) (Driver, error) {
	return nil, ErrNotSupported
	}