Undefined Variable 'data_nona' in Function '_pre_process_did'

[flowerpower13]

The function _pre_process_did references a variable named data_nona on lines 55, 56, 75, and 76. However, the variable data_nona is not defined within the scope of the function, which can lead to runtime errors and unexpected behavior when the function is executed.

Steps to Reproduce:

Navigate to the file containing the _pre_process_did function. Observe lines 5, 56, 75, and 76 where the variable data_nona is referenced.

[TJhon]

Thank you, there were indeed variable naming errors within preprocess_did.py, they have now been corrected in PR #16.