code: protected function initStyles(OutputInterface $output)
      {
          $this->colors = array(
              'green',
              'yellow',
              'cyan',
              'magenta',
              'blue',
          );
  
          foreach ($this->colors as $color) {
              $style = new OutputFormatterStyle($color);
              $output->getFormatter()->setStyle($color, $style);
          }
      }
docs: Init styles for tree
  
  @param OutputInterface $output