hey all, 
when coding and trying to do basic math with some variables im getting this error.
i want to show the user a picture the get an input, based on the user input he will get points:

class Player(BasePlayer):
    ...
    current_guess = models.IntegerField(label="Please guess the price of the stock in 20 days (day 100):", blank=False)
    
class pic1(Page):
    form_model = "player"
    form_fields = ['current_guess']
    if 0 <= abs(Player.current_guess - 150) < 20:
        Player.total_score += 20
    elif 20 <= abs(Player.current_guess - 150) - 150 < 50:
        Player.total_score += 10
    else:
        Player.total_score -= 20
        
this is the HTML file, done know if it matters:
{{ block title }}
    <div style="text-align: center;">
    First Graph
    </div>
{{ endblock }}

{{ block content }}
    <div style="text-align: center;">
    Your current score is {{ player.total_score }}
        <P><img src = "https://i.imgur.com/Fnuwkr4.gif"
             , alt = "DOGGIES!"
             , style = "width:250px;height:250px;">
        </P>
    </div>
        <P>
            {{ formfield "current_guess" }}
        </P>

    {{ next_button }}
{{ endblock }}
        
thank you in advance!