code: def test_str_key_sparse_to_dense(self) -> None:
      # string keys, set_missing_value_to_zero=True
      processor = StringKeySparseToDenseProcessor(
          self.sorted_features, set_missing_value_to_zero=True
      )
      value, presence = processor.process(self.str_keyed_sparse_data)
      assert torch.allclose(value, self.expected_value_0)
      assert torch.all(presence == self.expected_presence_0)
  
      # string keys, set_missing_value_to_zero=False
      processor = StringKeySparseToDenseProcessor(
          self.sorted_features, set_missing_value_to_zero=False
      )
      value, presence = processor.process(self.str_keyed_sparse_data)
      assert torch.allclose(value, self.expected_value_missing)
      assert torch.all(presence == self.expected_presence_missing)
  
file_path: ReAgent/reagent/test/preprocessing/test_sparse_to_dense.py
imports: import unittest
  import torch
  from reagent.preprocessing import normalization
  from reagent.preprocessing.sparse_to_dense import PythonSparseToDenseProcessor, StringKeySparseToDenseProcessor
label_desc: Use image node_id 3 for calling the TestSparseToDense obj's underlying member method code with example usage: obj.test_str_key_sparse_to_dense() without return types