Typegoose props not saving - node.js

Question

I'm having a problem using typegoose,
I have class like:
class UserType1 extends Typegoose
implements User{
#prop({required: true, unique: true})
_username: string | undefined;
#prop({required: true})
_password: string | undefined;
constructor(username:string, password: string){
this._username = username;
this._password = password;
}
async saveToDB(): Promis<void>{ // This method is refrenced inside User Interface
const model: ModelType<UserType1> = getModelForClass(UserType1);
await model.create(this);
}
<Other methods inside class>
}
Then I use the above code sequence like this:
const u: User = new UserType1("username", "password");
u.saveToDB();
then, a new record is saved inside UserType1 collection,
but it's empty. non of the _username, _password or other props are saved inside the record. Inside of it there's only _id and a variable called "__v" (which I don't know where it's come from.

Answer 1

from what i got as an answer in the comments about not using an unmaintained version, i would recommend to write your example in this way:
class UserType1 implements User {
#prop({ required: true, unique: true })
public _username!: string;
#prop({ required: true })
public _password!: string;
static async default(this: ReturnModelType<typeof UserType1>, username: string, password: string): Promise<void> {
await this.create({ _username: username, _password: password });
}
// <Other methods inside class>
}
const UserModel = getModelForClass(UserType1);
// somewhere in an async code block
await UserModel.default("user1", "somePassword");

Answer 2

Okay, So I left my code and started a new clean one, and It was working perfectly,
so I started investigating the difference between codes until I found out this small problem with importing packages, and it was unrelated to my code:
Instead of doing
import {prop} from "#typegoose/typegoose"
I was doing:
import {prop} from "typegoose"
Since it didn't give me any warning a worked without errors, I never realized this was the problem.
Hope this he