In config trees is common to see code like the following to turn a value into an array:

->beforeNormalization()
   ->ifTrue(function ($v) { return !is_array($v); })
    ->then(function ($v) { return array($v); })
->end()

// ...

->beforeNormalization()->ifString()->then(function ($v) { return array($v); })->end()

You can see it tens of times in Symfony, popular bundles and elsewhere. Could we add a helper method to remove this boilerplate code? Thanks!