code: func MsgOptionBlocks(blocks ...Block) MsgOption {
  	return func(config *sendConfig) error {
  		if blocks == nil {
  			return nil
  		}
  
  		blocks, err := json.Marshal(blocks)
  		if err == nil {
  			config.values.Set("blocks", string(blocks))
  		}
  		return err
  	}
  }
docs: // MsgOptionBlocks sets blocks for the message