code: public static function extract($yamlArray, $key, $needed = false)
      {
          if (!empty($yamlArray) && array_key_exists($key, $yamlArray))
              return $yamlArray[$key];
  
          if ($needed) {
              throw new \Deployer\Exception\Exception(
                  'Cannot find the setting: ' . $key . '. This key needs to be given!'
              );
          }
  
          return null; // The key was not needed, so continue!
      }
docs: Function for extracting keys from an yaml based array.
  
  @param array $yamlArray The array of matter
  @param mixed $key The key liked to be extracted
  @param bool $needed boolean if this key is needed (obligated)
  @return mixed|null The value or null when nothing was found
  
  @throws \Deployer\Exception\Exception When no key was found, but was needed