code: def get_file_ids(self, file_list, creator=None,
                       status=FileStatus.no_file, file_dict=None):
          
          ret_list = []
          for fname in file_list:
              if file_dict is None:
                  flags = FileFlags.no_flags
              else:
                  flags = file_dict.file_dict[fname]
              try:
                  fhandle = self.get_handle(fname)
              except KeyError:
                  if creator is None:
                      creator = -1
                      # raise KeyError("Can not register a file %s without a creator"%fname)
                  fhandle = self.register_file(fname, creator, status, flags)
              ret_list.append(fhandle.key)
          return ret_list
docs: Get or create a list of file ids based on file names
  
          Parameters
          ----------
  
          file_list : list
              The paths to the file
          creatror : int
              A unique key for the job that created these files
          status   : `FileStatus`
              Enumeration giving current status of files
          file_dict : `FileDict`
              Mask giving flags set on this file
  
          Returns list of integers