Hello! I want to programm the following:

You will create an experiment, where your subject’s task is to calculate the sum of two
randomly generated numbers between 1 and 100.
If the calculation is correct, your subject gets 1 point, if it is false, she gets 0 points.
You also need the random function, to generate two different random numbers
for your player
Hint: Generate the random numbers on your input page within the vars_for_template
function (fine for us for now!)
Hint: Assign the payoffs on your input page, by using the function:
before_next_page(player, timeout_happened)

I now have the following _init_ structure:
from otree.api import *
import random

doc = """
Experiment where participants calculate the sum of two randomly generated numbers
between 1 and 100. Participants earn 1 point for a correct answer and 0 points for an incorrect one.
"""


class Constants(BaseConstants):
    name_in_url = 'addition_task'
    players_per_group = None
    num_rounds = 1


class Subsession(BaseSubsession):
    def creating_session(self):
        for player in self.get_players():
            player.number1 = random.randint(1, 100)
            player.number2 = random.randint(1, 100)


class Group(BaseGroup):
    pass


class Player(BasePlayer):
    number1 = models.IntegerField()
    number2 = models.IntegerField()
    sum_input = models.IntegerField()
    score = models.IntegerField(initial=0)


class MyPage(Page):
    form_model = 'player'
    form_fields = ['sum_input']

    def vars_for_template(self):
        return {
            'number1': self.player.number1,
            'number2': self.player.number2
        }

    def before_next_page(self):
        correct_sum = self.player.number1 + self.player.number2
        if self.player.sum_input == correct_sum:
            self.player.score = 1
        else:
            self.player.score = 0


class Results(Page):
    def vars_for_template(self):
        return {
            'is_correct': self.player.score == 1,
            'correct_sum': self.player.number1 + self.player.number2
        }


page_sequence = [MyPage, Results]
But it does not work and says the following:
Unresolved attribute reference 'player' for class 'MyPage':40
Unresolved attribute reference 'player' for class 'MyPage':41
Signature of method 'MyPage.before_next_page()' does not match signature of the base method in class 'Page':44
Unresolved attribute reference 'player' for class 'MyPage':45
Unresolved attribute reference 'player' for class 'MyPage':45
Unresolved attribute reference 'player' for class 'MyPage':46
Unresolved attribute reference 'player' for class 'MyPage':47
Unresolved attribute reference 'player' for class 'MyPage':49
Unresolved attribute reference 'player' for class 'MyPage':55
Unresolved attribute reference 'player' for class 'MyPage':56
Unresolved attribute reference 'player' for class 'MyPage':56

Hello,

In both your posts, this one and the Stag Game, the issues stem from a misunderstanding of the parameters for functions inside a page class.

In older versions of oTree, these functions did indeed have a parameter named self. However, this has been outdated for a few years now. The newer versions of oTree use different parameters, usually player. (https://otree.readthedocs.io/en/latest/pages.html?highlight=vars_for_template#vars-for-template)

In your code, you still write the function as vars_for_template(self), but 'self' is just a name you defined for the player object that is passed to this function automatically. When you call 'self.player' inside the function, it actually tries to get a player object out of a player object (player.player), which causes errors. Same for 'self.group', it should be 'player.group'.

Rewrite your functions: rename the 'self' parameter to 'player', and use the 'player' parameter instead of 'self.player' in the functions.

Another outdated concept is the creating_session function that you defined inside your subsession class. The creating_session function is now defined at the same level as other classes. You should delete the line 'class Subsession(BaseSubsession):' and indent your function one level to the left to align it with others. (https://otree.readthedocs.io/en/latest/treatments.html?highlight=creating_session#creating-session)

Those might not be all the issues with your code, but it should get you started, and solve all of your existing errors.

Best regards and good luck,
Rok