code: def test_warning_if_unsortable_values(self, caplog):
      ranker = MetaFieldRanker(meta_field="rating")
      docs_before = [
          Document(id="1", content="abc", meta={"rating": 1.3}),
          Document(id="2", content="abc", meta={"rating": "1.2"}),
          Document(id="3", content="abc", meta={"rating": 2.1}),
      ]
      with caplog.at_level(logging.WARNING):
          output = ranker.run(documents=docs_before)
          assert len(output["documents"]) == 3
          assert (
              "Tried to sort Documents with IDs 1,2,3, but got TypeError with the message:"
              in caplog.text
          )
  
imports: import pytest
  import logging
  from haystack import Document
  from haystack.components.rankers.meta_field import MetaFieldRanker
label_desc: Use image node_id 10 for calling the TestMetaFieldRanker obj's underlying member method code with example usage: obj.test_warning_if_unsortable_values(caplog) without return types