code: def empty_strings():
      # dictionary
      d = h2o.H2OFrame({"e": ["", ""], "c": ["", ""], "f": ["", ""]})
      assert d.isna().sum().sum(axis=1)[:, 0] == 0
      assert (d == "").sum().sum(axis=1)[:, 0] == d.nrow * d.ncol
  
      # single list
      d = h2o.H2OFrame([""] * 4)
      assert d.isna().sum().sum(axis=1)[:, 0] == 0
      assert (d == "").sum().sum(axis=1)[:, 0] == d.nrow * d.ncol
  
      # list of lists
      d = h2o.H2OFrame([[""] * 4] * 3)
      assert d.isna().sum().sum(axis=1)[:, 0] == 0
      assert (d == "").sum().sum(axis=1)[:, 0] == d.nrow * d.ncol
  
label_desc: Use image node_id 1 for calling a global function with example usage: empty_strings() without return types