code: def chain_output_files(self):
          
          ret_list = []
          for key, val in self.file_dict.items():
              # For pure input files we only want output files that were not
              # marked as internal or temp
              if val & FileFlags.out_ch_mask == FileFlags.output_mask:
                  ret_list.append(key)
          return ret_list
docs: Return a list of the all the output files produced by this link.
  
          For `Link` sub-classes this will return only those files
          that were not marked as internal files or marked for removal.