code: func (t *SecureTrie) getSecKeyCache() map[string][]byte {
  	if t != t.secKeyCacheOwner {
  		t.secKeyCacheOwner = t
  		t.secKeyCache = make(map[string][]byte)
  	}
  	return t.secKeyCache
  }
docs: // getSecKeyCache returns the current secure key cache, creating a new one if
  // ownership changed (i.e. the current secure trie is a copy of another owning
  // the actual cache).