code: def get_instance(cls):
          
          if not cls.prepared:
              raise SingletonNotPreparedError(
                  "prepare must be called before get_instance"
              )
  
          if hasattr(cls.local, 'tchannel') and cls.local.tchannel is not None:
              return cls.local.tchannel
  
          cls.local.tchannel = cls.tchannel_cls(*cls.args, **cls.kwargs)
  
          return cls.local.tchannel
docs: Get a configured, thread-safe, singleton TChannel instance.
  
          :returns tchannel.TChannel: