metrics.py: Deprecated DataFrame.append()

[victorchang1001]

Hi,

Pandas 2.0.0 (April 3, 2023) have removed deprecated Series.append(), DataFrame.append() methods, and concat() should be used instead.

I'd like to suggest specifying the pandas version you used in requirements.txt to avoid errors (AttributeError: 'DataFrame' object has no attribute 'append')!

[Dheeraj-kkde]

Hi Victor,

You can resolve the above issue by using "_append" instead of "append".