docstr: Test that `DatasetDict` objects are different when they have same length
  but different keys.
docstr_tok: ["Test","that","`","DatasetDict","`","objects","are","different","when","they","have","same","length","but","different","keys","."]
code: def test_equality_same_length(self):
      """Test that `DatasetDict` objects are different when they have same length
      but different keys."""
      dset_dict = DatasetDict({"a": 1, "b": 2})
      assert dset_dict != {"a": 1, "c": 2}
  
file_path: pennylane/tests/data/attributes/test_dict.py
imports: import pytest
  from pennylane.data.attributes import DatasetDict
label_desc: Use image node_id 8 for calling the TestDatasetDict obj's underlying member method code with example usage: obj.test_equality_same_length() without return types