docs: def _system_path(self, subdir, basename=''):
          '''
          Gets the full path to the 'subdir/basename' file in the system binwalk directory.
  
          @subdir   - Subdirectory inside the system binwalk directory.
          @basename - File name inside the subdirectory.
  
          Returns the full path to the 'subdir/basename' file.
          '''
          try:
              return self._file_path(os.path.join(self.system_dir, subdir), basename)
          except KeyboardInterrupt as e:
              raise e
          except Exception:
              return None