code: protected function getPost($strKey)
  	{
  		if (\is_callable($this->inputCallback))
  		{
  			return \call_user_func($this->inputCallback);
  		}
  
  		if ($this->useRawRequestData === true)
  		{
  			/** @var Request $request */
  			$request = System::getContainer()->get('request_stack')->getCurrentRequest();
  
  			return $request->request->get($strKey);
  		}
  
  		$strMethod = $this->allowHtml ? 'postHtml' : 'post';
  
  		if ($this->preserveTags)
  		{
  			$strMethod = 'postRaw';
  		}
  
  		// Support arrays (thanks to Andreas Schempp)
  		$arrParts = explode('[', str_replace(']', '', $strKey));
  		$varValue = Input::$strMethod(array_shift($arrParts), $this->decodeEntities);
  
  		foreach ($arrParts as $part)
  		{
  			if (!\is_array($varValue))
  			{
  				break;
  			}
  
  			$varValue = $varValue[$part];
  		}
  
  		return $varValue;
  	}
docs: Find and return a $_POST variable
  
  @param string $strKey The variable name
  
  @return mixed The variable value