docs: def RenderJson(self, pretty=False):
          """
          Render a Tropo object into a Json string.
          """
          steps = self._steps
          topdict = {}
          topdict['tropo'] = steps
          if pretty:
              try:
                  json = jsonlib.dumps(topdict, indent=4, sort_keys=False)
              except TypeError:
                  json = jsonlib.dumps(topdict)
          else:
              json = jsonlib.dumps(topdict)
          return json