original_string: public static function getExtension($filename = '', $dot = false)
      {
          if (empty($filename)) {
              return '';
          }
          $exploded_file_name = explode('.', $filename);
          return (strpos($filename, '.') ? ($dot ? '.' : '').end($exploded_file_name) : null);
      }
code: public static function getExtension($filename = '', $dot = false)
      {
          if (empty($filename)) {
              return '';
          }
          $exploded_file_name = explode('.', $filename);
          return (strpos($filename, '.') ? ($dot ? '.' : '').end($exploded_file_name) : null);
      }
code_tokens: public static function getExtension ( $ filename = '' , $ dot = false ) { if ( empty ( $ filename ) ) { return '' ; } $ exploded_file_name = explode ( '.' , $ filename ) ; return ( strpos ( $ filename , '.' ) ? ( $ dot ? '.' : '' ) . end ( $ exploded_file_name ) : null ) ; }
docstring: Returns the extension of a file name
  
  It basically returns everything after last dot. No validation is done.
  
  @param   string  $filename  The file_name to work on
  @param   bool    $dot
  @return  null|string     The extension if found, `null` otherwise
docstring_tokens: Returns the extension of a file name