Question

Given the below cut down headache of a function, how would I go about calling a function on the utils.PrintingTemplateBase object that PrintingTemplate is inheriting?

I would also mention that PrintingTemplateBase requires an instance of itself to use (the closest being PrintingTemplate)

class PrintingTemplate (utils.PrintingTemplateBase) :

    #  Class used to accumulate lines of data
    #
    class LineData :

        #  Class constructor, optionally passed an existing instance in which case
        #  data is copied.
        #
        def __init__ (self, data = None) :

            self.number_of_panes            = 0
            self.material                   = ''  


    #--------------------------------------------------------------------------
    #
    #  LineData subclass for data coming from CalcGlass
    #
    class LineDataGlass (LineData) :

        def __init__ (self, calc_glass) :

            self.number_of_panes           = calc_glass.calc_component.calc_subitem.item.quantity
            try     : self.material        = calc_glass.glass_unit.workshop_description
            except  : self.material        = 'Undefined glass'


    def __init__(self) :

        utils.PrintingTemplateBase.__init__ (self)
        self.constants      = None

Answer 1

Python is not Java.

In Python, declaring a class inside another class does not give it any special access to the parent class. That’s why I said there’s almost never a good reason to do this.

If you need a LineData instance to have access to a PrintingTemplate instance, you’ll need to give it a reference to that instance, either by passing it into the __init__ method or by instantiating one directly there.