[FEATURE] Evaluation metrics to support any iterables

[Jun Ki Min]

Description

Current metrics only support pd.series.
Would be nice to work w/ any kinds of iterables like np.array, list, etc.

Expected behavior with the suggested feature

E.g.,

def MAPE(predictions, actuals):
    predictions = np.array(predictions)
    actuals = np.array(actuals)
    
    # mape calculation here
    np.absolute(predictions-actuals)  ...

[vapaunic]

@loomlike, good catch, will work on this.

[vapaunic]

Addressed in PR #158