code: def df_to_html(df, percentage_columns=None):  # pragma: no cover
      
      big_dataframe_setup()
      try:
          res = '<br><h2> {} </h2>'.format(df.name)
      except AttributeError:
          res = ''
      df.style.set_properties(**{'text-align': 'center'})
      res += df.to_html(formatters=_formatters_dict(
          input_df=df,
          percentage_columns=percentage_columns
      ))
      res += '<br>'
      return res
docs: Return a nicely formatted HTML code string for the given dataframe.
  
      Arguments
      ---------
      df : pandas.DataFrame
          A dataframe object.
      percentage_columns : iterable
          A list of cloumn names to be displayed with a percentage sign.
  
      Returns
      -------
      str
          A nicely formatted string for the given dataframe.