code: func (l *LFUNoTS) Set(key string, value interface{}) error {
  	return l.set(key, value)
  }
docs: // Set sets a new key-value pair
  // Set increments the key usage count too
  //
  // eg:
  // cache.Set("test_key","2")
  // cache.Set("test_key","1")
  // if you try to set a value into same key
  // its usage count will be increased
  // and usage count of "test_key" will be 2 in this example