class_docstr: Test case for the patch module.
class_docstr_tok: ["Test","case","for","the","patch","module","."]
code: def testCtxManager(self, _, model_builder):
      model = model_builder(self)
      mask = _get_used_params_mask(model, torch.rand(8, 4))
      opt = torch.optim.SGD(model.parameters(), lr=self.lr)
  
      with higher.innerloop_ctx(model, opt) as (fmodel, diffopt):
          for _ in range(10):
              inputs = torch.rand(8, 4)
              loss = fmodel(inputs).sum().pow(2)
              diffopt.step(loss)
          loss = fmodel(torch.rand(8, 4)).sum().pow(2)
          used_params = (
              p for p, g in zip(fmodel.parameters(time=0), mask) if g
          )
          final_grads = torch.autograd.grad(loss, used_params)
  
      for grad in final_grads:
          self.assertIsNotNone(grad)
  
imports: import unittest
  from parameterized import parameterized
  import torch
  from torch import nn
  import higher
label_desc: Use image node_id 7 for calling the TestPatch obj's underlying member method code with example usage: obj.testCtxManager(_, model_builder) without return types