If Condition Using with Parametrization

Hi,

I want to add some if conditions for my inputs to see in the user interface as like that;

tab_4 = Tab('New Inputs')
tab_4.example_if = Section("New Items")
tab_4.example_if.firstvariable =  NumberField('First Variable', suffix='kN', default=20)

if tab_4.example_if.firstvariable == 20:
    tab_4.example_if.secondvariable =  NumberField('Second Variable', suffix='kN', default=10)  
else:
    tab_4.example_if.thirdvariable =  NumberField('Third Variable', suffix='kN', default=20)

However, starting of the code I just saw the first and third variables on the screen even if first variable = 20. Am I doing something wrong or is not possible to use if condition for parametrization?

Thanks.

Okay I found the solution in the VIKTOR package.

Thanks.