error while using biom_to_stamp.py program .

For analysis of picrust tool result, I am using STAMP tool for kegg results. Input file needed for it should be in biom format.
I used the command as mentioned below
biom convert -i pred_metagenome_unstrat.tsv -o converted_table.biom --to-hdf5

./biom_to_stamp.py -m KEGG_Description ../converted_table.biom > ko.spf

After using 2nd command i am getting an error:

Traceback (most recent call last):
File "./biom_to_stamp.py", line 148, in
main()
File "./biom_to_stamp.py", line 125, in main
row=process_metadata(obs_metadata[metadata_name],metadata_name,obs_id)
TypeError: 'NoneType' object has no attribute 'getitem'

I am getting no clue on how to resolve this error. Any suggestions will be of great help. Thank you!

I'm afraid I don't know anything about this script, but based on the error the situation is the
obs_metadata variable is currently None.

I suspect you need to pass in the metadata file as well, but wouldn't know how to accomplish that. The script may have a --help flag you can call to learn more.