code: private function resolveOldConfig(array $configuration)
      {
          $newConfig = [
              'operators' => [],
          ];
  
          foreach ($configuration as $name => $setting) {
              if ('align_double_arrow' === $name) {
                  if (true === $configuration[$name]) {
                      $newConfig['operators']['=>'] = self::ALIGN;
                  } elseif (false === $configuration[$name]) {
                      $newConfig['operators']['=>'] = self::SINGLE_SPACE;
                  } elseif (null !== $configuration[$name]) {
                      throw new InvalidFixerConfigurationException(
                          $this->getName(),
                          sprintf(
                              'Invalid configuration: The option "align_double_arrow" with value %s is invalid. Accepted values are: true, false, null.',
                              $configuration[$name]
                          )
                      );
                  }
              } elseif ('align_equals' === $name) {
                  if (true === $configuration[$name]) {
                      $newConfig['operators']['='] = self::ALIGN;
                  } elseif (false === $configuration[$name]) {
                      $newConfig['operators']['='] = self::SINGLE_SPACE;
                  } elseif (null !== $configuration[$name]) {
                      throw new InvalidFixerConfigurationException(
                          $this->getName(),
                          sprintf(
                              'Invalid configuration: The option "align_equals" with value %s is invalid. Accepted values are: true, false, null.',
                              $configuration[$name]
                          )
                      );
                  }
              } else {
                  throw new InvalidFixerConfigurationException($this->getName(), 'Mixing old configuration with new configuration is not allowed.');
              }
          }
  
          $message = sprintf(
              'Given configuration is deprecated and will be removed in 3.0. Use configuration %s as replacement for %s.',
              HelpCommand::toString($newConfig),
              HelpCommand::toString($configuration)
          );
  
          if (getenv('PHP_CS_FIXER_FUTURE_MODE')) {
              throw new InvalidFixerConfigurationException($this->getName(), "{$message} This check was performed as `PHP_CS_FIXER_FUTURE_MODE` env var is set.");
          }
  
          @trigger_error($message, E_USER_DEPRECATED);
  
          return $newConfig;
      }
docs: @param array $configuration
  
  @return array