Call static method from string given class

Question

I have a JSON that user can modify outside my code. In that, I have full class name like:

models.InputLoader.InputLoader

When I load it in code, I get this a string representation. I want to call static method unseralize to which I pass another datum from JSON via dictionary.

InputLoader:
   @staticmethod
   def unserialize(d: Dict) -> InputLoader:
       return InputLoader(d["x"])

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

In JSON:

{
  "class": "models.InputLoader.InputLoader"
  "x": 45
}

How can I do this?