def delete(self, database, key, callback=None):
token = self._get_token()<EOL>self._enqueue(self._PendingItem(token, BlobCommand(token=token, database=database,<EOL>content=DeleteCommand(key=key.bytes)),<EOL>callback))<EOL>
Delete an item from the given database.

:param database: The database from which to delete the value.
:type database: .BlobDatabaseID
:param key: The key to delete.
:type key: uuid.UUID
:param callback: A callback to be called on success or failure.