code: def _print_dict_files(self, case, target):
          
          if case in self.live and target in self.live[case]:
              lines = []
              data = self.live[case][target]
              skeys = list(sorted(data.keys()))
              for key in skeys:
                  props = ", ".join(sorted(data[key].keys()))
                  lines.append("'{}': {}".format(key, props))
              return '\n'.join(lines)
          else:
              msg.err("Can't find the result set {} in {}".format(target, case))
docs: Prints the file names and available properties in the specified test case's 'target'
          dictionary.
          
          :arg case: the identifier of the test case to print contents for.
          :arg target: one of ['inputs', 'outputs', 'percent']