code: func (b *Bucket) Delete(key []byte) error {
  	if b.tx.db == nil {
  		return ErrTxClosed
  	} else if !b.Writable() {
  		return ErrTxNotWritable
  	}
  
  	// Move cursor to correct position.
  	c := b.Cursor()
  	_, _, flags := c.seek(key)
  
  	// Return an error if there is already existing bucket value.
  	if (flags & bucketLeafFlag) != 0 {
  		return ErrIncompatibleValue
  	}
  
  	// Delete the node if we have a matching key.
  	c.node().del(key)
  
  	return nil
  }
docs: // Delete removes a key from the bucket.
  // If the key does not exist then nothing is done and a nil error is returned.
  // Returns an error if the bucket was created from a read-only transaction.