Error in ParseFromString() while reading lmdb: Tag had invalid wire type

[ankan]

I am trying to read a lmdb in Python using the following code:

import caffe
import lmdb

be_env = lmdb.open('../be_train_lmdb')

be_txn = be_env.begin()
be_cursor = be_txn.cursor()

for key, value in be_cursor:
    datum = caffe.proto.caffe_pb2.Datum()
    datum.ParseFromString(value)
    print datum.label, datum.channels, datum.height, datum.width

I keep getting a decode error from ParseFromString():
google.protobuf.message.DecodeError: Tag had invalid wire type.

What could be wrong with this?

Thank you.