code: def test_format_value():
      assert format_value(None) == ""
      assert format_value(float("nan")) == "Missing"
      assert format_value(12.23333334) == "12.233"
      assert format_value(-12.23333334) == "-12.233"
  
label_desc: Use image node_id 2 for calling a global function with example usage: test_format_value() without return types