code: func (c *Clique) Authorize(signer common.Address, signFn SignerFn) {
  	c.lock.Lock()
  	defer c.lock.Unlock()
  
  	c.signer = signer
  	c.signFn = signFn
  }
docs: // Authorize injects a private key into the consensus engine to mint new blocks
  // with.