tree

type Tree interface {
	// Add places the block in the tree
	Add(snowman.Block)

	// Get returns the block that was added to this tree whose parent and ID
	// match the provided block. If non-exists, then false will be returned.
	Get(snowman.Block) (snowman.Block, bool)

	// Accept marks the provided block as accepted and rejects every conflicting
	// block.
	Accept(snowman.Block) error
}