code: def concat():
      df1 = h2o.create_frame(
          integer_fraction=1,
          binary_fraction=0,
          categorical_fraction=0,
          seed=1,
      )
      df2 = h2o.create_frame(
          integer_fraction=1,
          binary_fraction=0,
          categorical_fraction=0,
          seed=2,
      )
      df3 = h2o.create_frame(
          integer_fraction=1,
          binary_fraction=0,
          categorical_fraction=0,
          seed=3,
      )
  
      # Frame to Frame concat (column-wise)
      df123 = df1.concat([df2, df3])
      rows, cols = df123.dim
      assert (
          rows == 10000 and cols == 30
      ), "unexpected dimensions in column concatenation for a Frame"
  
      # Frame to Frame concat (row wise)
      df123_row = df1.concat([df2, df3], axis=0)
      rows2, cols2 = df123_row.dim
      assert (
          rows2 == 30000 and cols2 == 10
      ), "unexpected dimensions in row concatenation for a Frame"
  
      # Frame to Vec concat (column wise)
      yy = df2[0]
      zz = df3[0]
      hdf = df1.concat([yy, zz])
      rows3, cols3 = hdf.dim
      assert (
          rows3 == 10000 and cols3 == 12
      ), "unexpected dimensions in Frame to Vec concatenation"
  
      # Vec to Vec concat (column wise)
      xx = df1[0]
      yy = df2[0]
      zz = df3[0]
      hdf2 = xx.concat([yy, zz])
      rows4, cols4 = hdf2.dim
      assert (
          rows4 == 10000 and cols4 == 3
      ), "unexpected dimensions in Vec to Vec concatenation"
  
      # Frame to Vec concat (row wise)
      yy = df2[0, :]
      zz = df3[0, :]
      hdf3 = df1.concat([yy, zz], axis=0)
      rows5, cols5 = hdf3.dim
      assert (
          rows5 == 10002 and cols5 == 10
      ), "unexpected dimensions in Frame to Vec concatenation"
  
      # Vec to Vec concat (row wise)
      xx = df1[0, :]
      yy = df2[0, :]
      zz = df3[0, :]
      hdf4 = xx.concat([yy, zz], axis=0)
      rows6, cols6 = hdf4.dim
      assert (
          rows6 == 3 and cols6 == 10
      ), "unexpected dimensions in Vec to Vec concatenation"
  
label_desc: Use image node_id 1 for calling a global function with example usage: concat() without return types