code: def length_check():
      # Connect to a pre-existing cluster
  
      # Test on strings
      frame = h2o.import_file(
          path=pyunit_utils.locate("smalldata/junit/names.csv"),
          col_types=["string", "string", "numeric"],
      )
  
      # single column (frame)
      # UTF strings
      length_frame = frame["name1"].nchar()
      assert length_frame[0, 0] == 4, "Expected 4, but got {}".format(
          length_frame[0, 0]
      )
      assert length_frame[1, 0] == 3, "Expected 3, but got {}".format(
          length_frame[1, 0]
      )
      assert length_frame[2, 0] == 4, "Expected 4, but got {}".format(
          length_frame[2, 0]
      )
      # ASCII only strings
      length_frame = frame["name2"].nchar()
      assert length_frame[0, 0] == 4, "Expected 4, but got {}".format(
          length_frame[0, 0]
      )
      assert length_frame[1, 0] == 3, "Expected 3, but got {}".format(
          length_frame[1, 0]
      )
      assert length_frame[2, 0] == 4, "Expected 4, but got {}".format(
          length_frame[2, 0]
      )
  
      # single column (vec)
      vec = frame["name1"]
      trimmed_vec = vec.trim()
      length_vec = trimmed_vec.nchar()
      assert length_vec[0, 0] == 4, "Expected 4, but got {}".format(
          length_vec[0, 0]
      )
      assert length_vec[1, 0] == 3, "Expected 3, but got {}".format(
          length_vec[1, 0]
      )
      assert length_vec[2, 0] == 4, "Expected 4, but got {}".format(
          length_vec[2, 0]
      )
  
label_desc: Use image node_id 1 for calling a global function with example usage: length_check() without return types