code: def h2o_H2OFrame_sub():
      """
      Python API test: h2o.frame.H2OFrame.sub(pattern, replacement, ignore_case=False)
  
      Copied from pyunit_substring.py
      """
      frame = h2o.import_file(
          path=pyunit_utils.locate("smalldata/iris/iris.csv")
      )
      frame["C5"] = frame["C5"].sub("s", "z", ignore_case=False)
      assert (
          frame[1, 4] == "Iriz-setosa"
      ), "Expected 'Iriz-setosa', but got {0}".format(frame[1, 4])
  
label_desc: Use image node_id 1 for calling a global function with example usage: h2o_H2OFrame_sub() without return types