Add block to the database.

ContextualValidity returns tuples with block id and contextual validity for all blocks in the layer.

Get block with id from database.

GetLayer returns the layer of a block.

Has a block in the database.

IDsInLayer returns list of block ids in the layer.

IsValid returns true if block is verified.

Layer returns full body blocks for layer.

SetInvalid updates blocks to an invalid status.

SetValid updates verified status for a block.