code: def test_string_conversion_function(function):
      values = [
          [12.5, "fdsa", "aa"],
          [22.2, "f343", "aa"],
          [32.3, "4323", "bb"],
          [-2.3, "3223", "bb"],
      ]
      frame = h2o.H2OFrame(
          python_obj=values,
          column_names=["a", "b", "c"],
          column_types=["numeric", "string", "enum"],
      )
      assembly = H2OAssembly(
          steps=[
              (
                  "col_op1_" + function.__name__,
                  H2OColOp(
                      op=function,
                      col="a",
                      new_col_name="x",
                      inplace=False,
                  ),
              ),
              (
                  "col_op2_" + function.__name__,
                  H2OColOp(
                      op=function,
                      col="b",
                      new_col_name="y",
                      inplace=False,
                  ),
              ),
              (
                  "col_op3_" + function.__name__,
                  H2OColOp(
                      op=function,
                      col="c",
                      new_col_name="z",
                      inplace=False,
                  ),
              ),
          ]
      )
  
      expected = assembly.fit(frame)
      assert_is_type(expected, H2OFrame)
  
      results_dir = os.path.join(os.getcwd(), "results")
      file_name = (
          "h2oassembly_download_mojo_col_op_" + function.__name__
      )
      path = os.path.join(results_dir, file_name + ".mojo")
  
      mojo_file = assembly.download_mojo(file_name=file_name, path=path)
      assert os.path.exists(mojo_file)
  
      pipeline = H2OMojoPipeline(mojo_path=mojo_file)
      result = pipeline.transform(frame)
      assert_is_type(result, H2OFrame)
  
      pyunit_utils.compare_frames(
          expected, result, expected.nrows, tol_numeric=1e-5
      )
  
imports: import sys, os
  from tests import pyunit_utils
  from h2o.assembly import *
  from h2o.transforms.preprocessing import *
  from h2o.pipeline import H2OMojoPipeline
label_desc: Use image node_id 2 for calling a global function with example usage: test_string_conversion_function(function) without return types