Dummy sets_stats_df if sets is not None but is empty

[JoeRibeiro]

Hi @jiho

Amy & I at Cefas tested on a file with no defined sets and the converted_data.json came out containing:

"set_information": {
"definition": "",
"statistics": []
},

It tripped up causing the error:

Error processing 'converted_data.json': cannot access local variable 'sets_stats_df' where it is not associated with a value

Because set_information was present as an empty dictionary (not none) and sets_stats_df is only created inside the loop over set_information["statistics"]

This small fix seemed to unstick things. Cheers,
Joe

[jiho]

I think the key here is that the test if sets is None is not the correct one. It should be None or of length 0. Can you please send and example file where this fails to that I can reproduce it?