TCA::insertOptions() 

\nn\t3::TCA()->insertOptions($config, $a = NULL); 

Inserts options from TypoScript into a TCA for selection. Alias to nnt3::Flexform->insertOptions( $config, $a = null ); Description and further examples there.

Example in the TCA:

'config' => [
    'type' => 'select',
    'itemsProcFunc' => 'nn\t3\Flexform->insertOptions',
    'typoscriptPath' => 'plugin.tx_nnnewsroom.settings.templates',
    //'pageconfigPath' => 'tx_nnnewsroom.colors',
]

| @return array

public function insertOptions ( $config, $a = null )
{
	return \nn\t3::Flexform()->insertOptions( $config, $a );
}