code: func (s *ReadState) GetAccount(address crypto.Address) (*acm.Account, error) {
  	tree, err := s.Forest.Reader(keys.Account.Prefix())
  	if err != nil {
  		return nil, err
  	}
  	accBytes := tree.Get(keys.Account.KeyNoPrefix(address))
  	if accBytes == nil {
  		return nil, nil
  	}
  	return acm.Decode(accBytes)
  }
docs: // Returns nil if account does not exist with given address.