code: def test_rename_payload_keys():
      payload = {
          "old_key1": "value1",
          "old_key2": "value2",
          "old_key3": None,
          "old_key4": [],
      }
      mapping = {"old_key1": "new_key1", "old_key2": "new_key2"}
      expected = {
          "new_key1": "value1",
          "new_key2": "value2",
          "old_key3": None,
          "old_key4": [],
      }
      assert rename_payload_keys(payload, mapping) == expected
  
imports: import pytest
  from mlflow.gateway.providers.utils import rename_payload_keys
label_desc: Use image node_id 1 for calling a global function with example usage: test_rename_payload_keys() without return types