code: def new_filehandler_instances(self, filetype_info, filename_items, fh_kwargs=None):
          
          requirements = filetype_info.get('requires')
          filetype_cls = filetype_info['file_reader']
  
          if fh_kwargs is None:
              fh_kwargs = {}
  
          for filename, filename_info in filename_items:
              try:
                  req_fh = self.find_required_filehandlers(requirements,
                                                           filename_info)
              except KeyError as req:
                  msg = "No handler for reading requirement {} for {}".format(
                      req, filename)
                  warnings.warn(msg)
                  continue
              except RuntimeError as err:
                  warnings.warn(str(err) + ' for {}'.format(filename))
                  continue
  
              yield filetype_cls(filename, filename_info, filetype_info, *req_fh, **fh_kwargs)
docs: Generate new filehandler instances.