RuntimeWarning: invalid value encountered in divide

[tentato]

While playing with the ComplexityCalculator(), I noticed this warning for f1 and f2 measures, which leads to a return = nan.

For f1:

C:\Users\***\AppData\Roaming\Python\Python311\site-packages\problexity\classification\feature_based.py:45: RuntimeWarning: invalid value encountered in divide
  r_all = l/m

For f2:

C:\Users\***\AppData\Roaming\Python\Python311\site-packages\problexity\classification\feature_based.py:141: RuntimeWarning: invalid value encountered in divide
  return np.product(f_overlap/f_range)