Binding::ensureExactlyOnePrimaryBoundEntityExists

private function ensureExactlyOnePrimaryBoundEntityExists(Collection $bindingsCollection, array $providedBindings): int
{
	$idOfPrimaryBoundEntity = $this->selectPrimaryBoundEntity($bindingsCollection, $providedBindings);

	foreach ($bindingsCollection as $bindingObject)
	{
		if ($bindingObject->get($this->boundEntityIdFieldName) === $idOfPrimaryBoundEntity)
		{
			$bindingObject->set('IS_PRIMARY', true);
		}
		else
		{
			$bindingObject->set('IS_PRIMARY', false);
		}
	}

	return $idOfPrimaryBoundEntity;
}