in src/smclarify/bias/metrics/basic_stats.py [0:0]
def proportion(sensitive_facet_index: pd.Series) -> float:
r"""
Proportion of examples in sensitive facet.
:param sensitive_facet_index: boolean column indicating sensitive group
:return: the fraction of examples in the sensitive facet.
"""
return sum(sensitive_facet_index) / len(sensitive_facet_index)