How to convert nested classes to json or dict?

Question

I have class of classes as below:

class Base:
  def __init__(self):
    self.var1 = “variable”

class Child:
  def __init__(self):
    self.base = Base()
    self.var2 = False

class RootChild:
  def __init__(self):
    self.child = Child()
    self.var3 = “variable”
    self.base = Base()

I want to save an instance of ‘RootChild’ with all fields of it represented in json. There are a lot of topics about this task, but I could not understand their differences and use cases. What are most pythonic solutions to this problem?