how to retrieve map of map object data from firebase

Question

I am trying to retrieve the values of doctors map object as list of {times, email} for a specific date.

this is the code i have tried so far:

Stream<List> fromDateToList(int day, int month, int year){
var val = usersInfoCollection
    .doc(uid).get();
Map<String, dynamic> data = {};
return usersInfoCollection
    .doc(uid)
    .snapshots()
    .map((doc) {
  if (doc['doctors'] is Map) {
    return doc['doctors'].values.toList();
  } else {
    return [];
  }
});

}