docs: def bar3_chart(self, title, labels, data1, file_name, data2, data3, legend=["", ""]):
          """
          Generate a bar plot with three columns in each x position and save it to file_name
  
          :param title: title to be used in the chart
          :param labels: list of labels for the x axis
          :param data1: values for the first columns
          :param file_name: name of the file in which to save the chart
          :param data2: values for the second columns
          :param data3: values for the third columns
          :param legend: legend to be shown in the chart
          :return:
          """
  
          colors = ["orange", "grey"]
  
          data1 = self.__convert_none_to_zero(data1)
          data2 = self.__convert_none_to_zero(data2)
          data3 = self.__convert_none_to_zero(data3)
  
          fig, ax = plt.subplots(1)
          xpos = np.arange(len(data1))
          width = 0.28
  
          plt.title(title)
          y_pos = np.arange(len(data1))
  
          ppl.bar(xpos + width + width, data3, color="orange", width=0.28, annotate=True)
          ppl.bar(xpos + width, data1, color='grey', width=0.28, annotate=True)
          ppl.bar(xpos, data2, grid='y', width=0.28, annotate=True)
          plt.xticks(xpos + width, labels)
          plt.legend(legend, loc=2)
  
          os.makedirs(os.path.dirname(file_name), exist_ok=True)
          plt.savefig(file_name)
          plt.close()