code: public function initPicker(PickerInterface $picker)
  	{
  		if (!empty($_GET['act']))
  		{
  			return null;
  		}
  
  		$provider = $picker->getCurrentProvider();
  
  		if (!$provider instanceof DcaPickerProviderInterface || $provider->getDcaTable() != $this->strTable)
  		{
  			return null;
  		}
  
  		$attributes = $provider->getDcaAttributes($picker->getConfig());
  
  		$this->objPicker = $picker;
  		$this->strPickerFieldType = $attributes['fieldType'];
  
  		$this->objPickerCallback = function ($value) use ($picker, $provider)
  		{
  			return $provider->convertDcaValue($picker->getConfig(), $value);
  		};
  
  		if (isset($attributes['value']))
  		{
  			$this->arrPickerValue = (array) $attributes['value'];
  		}
  
  		return $attributes;
  	}
docs: Initialize the picker
  
  @param PickerInterface $picker
  
  @return array|null