code: func (c *Clique) APIs(chain consensus.ChainReader) []rpc.API {
  	return []rpc.API{{
  		Namespace: "clique",
  		Version:   "1.0",
  		Service:   &API{chain: chain, clique: c},
  		Public:    false,
  	}}
  }
docs: // APIs implements consensus.Engine, returning the user facing RPC API to allow
  // controlling the signer voting.