code: def _GetFlowArgsHelpAsString(self, flow_cls):
      
      output = [
          "  Call Spec:",
          "    %s" % self._GetCallingPrototypeAsString(flow_cls), ""
      ]
      arg_list = sorted(
          iteritems(self._GetArgsDescription(flow_cls.args_type)),
          key=lambda x: x[0])
      if not arg_list:
        output.append("  Args: None")
      else:
        output.append("  Args:")
        for arg, val in arg_list:
          output.append("    %s" % arg)
          output.append("      description: %s" % val["description"])
          output.append("      type: %s" % val["type"])
          output.append("      default: %s" % val["default"])
          output.append("")
      return "\n".join(output)
docs: Get a string description of the calling prototype for this flow.