code: def get_new(self):
          
  
          # refresh files
          self.refresh()
          # current files
          new_info = self._load()
          # previous set of files
          old_info = self._load(prev_version=True)
          new_files = new_info[-new_info.isin(old_info)]
          return new_files
docs: List new files since last recorded file state.
          
          pysat stores filenames in the user_home/.pysat directory. Returns
          a list of all new fileanmes since the last known change to files.
          Filenames are stored if there is a change and either update_files
          is True at instrument object level or files.refresh() is called.
          
          Returns
          -------
          pandas.Series
              files are indexed by datetime