code: func (h *Hash) SetBytes(hash []byte) error {
  	if length := len(hash); length != common.HashLength {
  		return fmt.Errorf("invalid hash length: %v != %v", length, common.HashLength)
  	}
  	copy(h.hash[:], hash)
  	return nil
  }
docs: // SetBytes sets the specified slice of bytes as the hash value.