Problems encountered when reading LMDB files

Hello, OCP team!
Recently I used VASP to calculate some of the structures I need to use. But I ran into problems when I wrote the OUTCAR information to the LMDB file and read it. When I wrote the OUTCAR information to the LMDB file, I simply changed the path to which the file was written and got two files. Both LMDB files contain information from the same OUTCAR. However, when I read the information in the LMBD files using the ‘LmdbDataset’ function separately, I can read the OUTCAR information from one LMDB file, and the other LMDB file gets an error when reading. Python reminds me that " TypeError: a bytes-like object is required, not ‘NoneType’ ”. I uploaded these two files, you can get them through this link. LMDB
The LMDB file in folder 0 can be read successfully. The LMDB file in the folder named 1 cannot be read.
Can you help me solve this problem. Thank you.

Hi -

This error usually happens when the “length” key is not attached to the LMDB i.e. ocp/scripts/preprocess_ef.py at daf72a502c6ee19f2c70eaef58eefc233f25362c · Open-Catalyst-Project/ocp · GitHub. If you share the code used to generate this I can better assist you.