code: func (st *State) CreateAccount(address crypto.Address) {
  	if st.Exists(address) {
  		st.PushError(errors.ErrorCodef(errors.ErrorCodeDuplicateAddress,
  			"tried to create an account at an address that already exists: %v", address))
  		return
  	}
  	st.updateAccount(&acm.Account{Address: address})
  }
docs: // Writer