如何使用子类的数据调用超类方法？

Question

I'm parsing data from an XML file and I need to convert some of it to integers - when setting them to attributes of the B class. Since I have multiple subclasses, I'm trying to write the code once in the superclass instead of having to write it in each subclass.

class A:

  def __setattr__(self, name, value):
    if isinstance(__class__.__dict__[name], int):
      self.__dict__[name] = int(value)

class B(A):

  val = int()

  def __init__(self, val):
    self.val = val


b = B("4")
print(type(b.val))

My problem is that __class__ and self refer to the superclass. I need the ones from the subclasses. Any ideas?

---

I'm not sure if I explain my problem very well, so here is the code if I had to do it only for one class:

class A:
  val = int()

  def __init__(self, val1): #val1 is a string
    self.val = val1

  def __setattr__(self, name, value):
    if isinstance(A.__dict__[name], int):
      self.__dict__[name] = int(value)

b = A("4")
print(type(b.val)) #prints <class 'int'>

Answer 1

Use a classmethod to get the derived class and pass the known self as a parameter

class A:

  def __setattr__(self, name, value):
    self._setter(self, name, value)

  @classmethod
  def _setter(cls, self, name, value):
      if isinstance(getattr(cls, name), int):
         self.__dict__[name] = int(value)

class B(A):

  val = int()

  def __init__(self, val):
    self.val = val


b = B("4")
print(type(b.val), b.val)

Instead of assigning a variable and using its type, you could just assign the type itself in the class. I've put it all in a dict called schema because that seems to document better what is going on to me.

class A:

  schema = {}

  def __setattr__(self, name, value):
    self._setter(self, name, value)

  @classmethod
  def _setter(cls, self, name, value):
      if name in cls.schema:
          value = cls.schema[name](value)
      self.__dict__[name] = value

class B(A):

  schema = {"val":int}

  def __init__(self, val):
      self.val = val

b = B("4")
print(type(b.val), b.val)