code: ##############################################################################
  #
  # An example of converting a Pandas dataframe to an xlsx file with a grouped
  # column chart using Pandas and XlsxWriter.
  #
  # Copyright 2013-2019, John McNamara, jmcnamara@cpan.org
  #
  
  import pandas as pd
  
  # Some sample data to plot.
  farm_1 = {'Apples': 10, 'Berries': 32, 'Squash': 21, 'Melons': 13, 'Corn': 18}
  farm_2 = {'Apples': 15, 'Berries': 43, 'Squash': 17, 'Melons': 10, 'Corn': 22}
  farm_3 = {'Apples': 6,  'Berries': 24, 'Squash': 22, 'Melons': 16, 'Corn': 30}
  farm_4 = {'Apples': 12, 'Berries': 30, 'Squash': 15, 'Melons': 9,  'Corn': 15}
  
  data  = [farm_1, farm_2, farm_3, farm_4]
  index = ['Farm 1', 'Farm 2', 'Farm 3', 'Farm 4']
  
  # Create a Pandas dataframe from the data.
  df = pd.DataFrame(data, index=index)
  
  # Create a Pandas Excel writer using XlsxWriter as the engine.
  sheet_name = 'Sheet1'
  writer     = pd.ExcelWriter('pandas_chart_columns.xlsx', engine='xlsxwriter')
  df.to_excel(writer, sheet_name=sheet_name)
  
  # Access the XlsxWriter workbook and worksheet objects from the dataframe.
  workbook  = writer.book
  worksheet = writer.sheets[sheet_name]
  
  # Create a chart object.
  chart = workbook.add_chart({'type': 'column'})
  
  # Some alternative colors for the chart.
  colors = ['#E41A1C', '#377EB8', '#4DAF4A', '#984EA3', '#FF7F00']
  
  # Configure the series of the chart from the dataframe data.
  for col_num in range(1, len(farm_1) + 1):
      chart.add_series({
          'name':       ['Sheet1', 0, col_num],
          'categories': ['Sheet1', 1, 0, 4, 0],
          'values':     ['Sheet1', 1, col_num, 4, col_num],
          'fill':       {'color':  colors[col_num - 1]},
          'overlap':    -10,
      })
  
  # Configure the chart axes.
  chart.set_x_axis({'name': 'Total Produce'})
  chart.set_y_axis({'name': 'Farms', 'major_gridlines': {'visible': False}})
  
  # Insert the chart into the worksheet.
  worksheet.insert_chart('H2', chart)
  
  # Close the Pandas Excel writer and output the Excel file.
  writer.save()
  
apis: pandas.ExcelWriter pandas.DataFrame