class_docstr: self = TestOptimize()
  self.setUp()
code: def loss_fn(self, params, loss_params):
      A = params["A"]
      B = loss_params["B"]
  
      return (A - B).pow(2).sum()
  
file_path: pgmpy/pgmpy/tests/test_utils/test_optimizer.py
imports: import unittest
  import numpy
  import numpy.testing
  import torch
  from pgmpy import config
  from pgmpy.utils import optimize, pinverse
label_desc: Use image node_id 2 for calling the TestOptimize obj's underlying member method code with example usage: obj.loss_fn(params, loss_params) and returns: unknown