original_string: public static function add($key, $value, $config = 'default')
      {
          $pool = static::pool($config);
          if (is_resource($value)) {
              return false;
          }
  
          return $pool->add($key, $value);
      }
code: public static function add($key, $value, $config = 'default')
      {
          $pool = static::pool($config);
          if (is_resource($value)) {
              return false;
          }
  
          return $pool->add($key, $value);
      }
code_tokens: public static function add ( $ key , $ value , $ config = 'default' ) { $ pool = static :: pool ( $ config ) ; if ( is_resource ( $ value ) ) { return false ; } return $ pool -> add ( $ key , $ value ) ; }
docstring: Write data for key into a cache engine if it doesn't exist already.
  
  ### Usage:
  
  Writing to the active cache config:
  
  ```
  Cache::add('cached_data', $data);
  ```
  
  Writing to a specific cache config:
  
  ```
  Cache::add('cached_data', $data, 'long_term');
  ```
  
  @param string $key Identifier for the data.
  @param mixed $value Data to be cached - anything except a resource.
  @param string $config Optional string configuration name to write to. Defaults to 'default'.
  @return bool True if the data was successfully cached, false on failure.
  Or if the key existed already.
docstring_tokens: Write data for key into a cache engine if it doesn t exist already .