code: def assembly_demo():
      fr = h2o.import_file(
          pyunit_utils.locate("smalldata/iris/iris_wheader.csv"),
          col_types=[
              "numeric",
              "numeric",
              "numeric",
              "numeric",
              "string",
          ],
      )  # import data
      assembly = H2OAssembly(
          steps=[
              (
                  "col_select",
                  H2OColSelect(["sepal_len", "petal_len", "class"]),
              ),  # col selection
              (
                  "cos_sep_len",
                  H2OColOp(
                      op=H2OFrame.cos, col="sepal_len", inplace=True
                  ),
              ),  # math operation
              (
                  "str_cnt_species",
                  H2OColOp(
                      op=H2OFrame.countmatches,
                      col="class",
                      inplace=False,
                      pattern="s",
                  ),
              ),
          ]
      )  # string operation
  
      result = assembly.fit(fr)  # fit the assembly
      result.show()  # show the result of the fit
  
      assembly.to_pojo("MungingPojoDemo")
  
imports: import sys
  import h2o
  from tests import pyunit_utils
  from h2o.assembly import H2OAssembly
  from h2o.transforms.preprocessing import *
  from h2o import H2OFrame
label_desc: Use image node_id 1 for calling a global function with example usage: assembly_demo() without return types