Function datafusion_physical_expr::utils::normalize_ordering_equivalence_classes

pub fn normalize_ordering_equivalence_classes(
    oeq_classes: &[OrderingEquivalentClass],
    eq_properties: &EquivalenceProperties
) -> Vec<OrderingEquivalentClass>

This function “normalizes” its argument oeq_classes by making sure that it only refers to representative (i.e. head) entries in the given equivlance properties (eq_properties).