   end
 
   defp check_cfg_fld_type(excg, fld, rows) do
-    header_rows = header_rows
+    header_rows = header_rows()
     fld_name = fld.name
     type = excg.type_map[fld.type]
     for {row, i} <- Enum.with_index(rows) do

  end

  defp check_cfg_fld_sequence(excg, fld, rows) do
    header_rows = header_rows
    fld_name = fld.name
    opt = Keyword.get(fld.opts, :sequence)
    Enum.reduce(Enum.with_index(rows), opt, fn({row, i}, {start, step}) ->

  end

  defp check_cfg_fld_cfun(excg, fld, cfun, rows) do
    header_rows = header_rows()
    fld_name = fld.name
    {fun_name, fun_opts} = cfun
    for {row, i} <- Enum.with_index(rows) do
