prow/plugins/approve/approvers/owners.go
func (o Owners) GetReverseMap(approvers map[string]sets.String) map[string]sets.String {
	approverOwnersfiles := map[string]sets.String{}
	for ownersFile, approvers := range approvers {
		for approver := range approvers {
			if _, ok := approverOwnersfiles[approver]; ok {
				approverOwnersfiles[approver].Insert(ownersFile)
			} else {
				approverOwnersfiles[approver] = sets.NewString(ownersFile)
			}
		}
	}
	return approverOwnersfiles
}
func (o Owners) GetReverseMap(approvers map[string]sets.String) map[string]sets.String {
	approverOwnersfiles := map[string]sets.String{}
	for ownersFile, approvers := range approvers {
		for approver := range approvers {
			if _, ok := approverOwnersfiles[approver]; ok {
				approverOwnersfiles[approver].Insert(ownersFile)
			} else {
				approverOwnersfiles[approver] = sets.NewString(ownersFile)
			}
		}
	}
	return approverOwnersfiles
}
// GetReverseMap returns a map from people -> OWNERS files for which they are an approver