code: func (tx *Tx) CreateBucketIfNotExists(name []byte) (*Bucket, error) {
  	return tx.root.CreateBucketIfNotExists(name)
  }
docs: // CreateBucketIfNotExists creates a new bucket if it doesn't already exist.
  // Returns an error if the bucket name is blank, or if the bucket name is too long.
  // The bucket instance is only valid for the lifetime of the transaction.