class RSpec::Matchers::BuiltIn::ContainExactly::PairingsMaximizer

def categorize_indexes(indexes_to_categorize, other_indexes)
  unmatched     = []
  indeterminate = []
  indexes_to_categorize.each_pair do |index, matches|
    if matches.empty?
      unmatched << index
    elsif !reciprocal_single_match?(matches, index, other_indexes)
      indeterminate << index
    end
  end
  return unmatched, indeterminate
end