def __init__(self, db, write=False, stats=None):
self._db = db<EOL>self._write = write<EOL>self._stats = stats<EOL>self._txn = None<EOL>self._log = None<EOL>
:param db:
:type db: zlmdb.Database

:param write:
:type write: bool

:param stats:
:type stats: TransactionStats