Flutter Future Filtered Data - flutter

Question

I'm pulling my data from MongoDB with a Future. However, I want to pull only some of the data, not the whole data. How can I filter this?
I will put the data I filtered into the list. I added the readMongo and lessonModel codes.
In addition, although my codes work very well, I think that I did not do something according to the rules, if I am missing, I would be very happy if you could point out.
Future<List<Map<String, dynamic>>> _getData() async {
values = MongoDatabase.readMongo(MongoDatabase.lessonCollection);
return values!;
}
readMongo
static Future<List<Map<String, dynamic>>> readMongo(collectionName) async {
final data = await collectionName.find().toList();
return data;
}
LessonModel
import 'dart:convert';
LessonModel lessonModelFromMap(String str) => LessonModel.fromMap(json.decode(str));
String lessonModelToMap(LessonModel data) => json.encode(data.toMap());
class LessonModel {
LessonModel({this.id, this.info, this.subject});
final Id? id;
final Info? info;
final List<Subject>? subject;
factory LessonModel.fromMap(Map<String, dynamic> json) => LessonModel(
info: json["info"] == null ? null : Info.fromMap(json["info"]),
subject: json["subject"] == null ? null : List<Subject>.from(json["subject"].map((x) => Subject.fromMap(x))),
);
Map<String, dynamic> toMap() => {
"_id": id == null ? null : id!.toMap(),
"info": info == null ? null : info!.toMap(),
"subject": subject == null ? null : List<dynamic>.from(subject!.map((x) => x.toMap())),
};
}
class Id {
Id({this.oid});
final String? oid;
factory Id.fromMap(Map<String, dynamic> json) => Id(oid: json["\u0024oid"]);
Map<String, dynamic> toMap() => {"\u0024oid": oid};
}
class Info {
Info({this.name, this.infoClass, this.semester, this.credit, this.icon});
final String? name;
final String? infoClass;
final String? semester;
final int? credit;
final String? icon;
factory Info.fromMap(Map<String, dynamic> json) => Info(
name: json["name"],
infoClass: json["class"],
semester: json["semester"],
credit: json["credit"],
icon: json["icon"]);
Map<String, dynamic> toMap() =>
{"name": name, "class": infoClass, "semester": semester, "credit": credit, "icon": icon};
}
class Subject {
Subject({this.subjectId, this.name, this.text, this.video, this.trainer});
final int? subjectId;
final String? name;
final String? text;
final String? video;
final String? trainer;
factory Subject.fromMap(Map<String, dynamic> json) => Subject(
subjectId: json["subjectId"],
name: json["name"],
text: json["text"],
video: json["video"],
trainer: json["trainer"]);
Map<String, dynamic> toMap() =>
{"subjectId": subjectId, "name": name, "text": text, "video": video, "trainer": trainer};
}