public function getPresentationRoleHypercubes( $roleKey )
	{
		/**
		 * @var array $refs
		 */
		$refs = $this->context->presentationRoleRefs;

		if ( ! isset( $refs[ $roleKey ] ) ) return array();
		return isset( $refs[ $roleKey ]['hypercubes'] )
			? $refs[ $roleKey ]['hypercubes']
			: array();
	}