code: def import_source(self, sheet, source, delimiter=","):
          
          # check input parameters
          if ' ' in sheet:
              raise RuntimeError("Error sheet name: %s" % sheet)
  
          if not source.endswith("txt") and not source.endswith("csv"):
              raise RuntimeError("Error source name: %s" % source)
  
          self.source_sheet = sheet
  
          source_data = np.loadtxt(source, dtype=str, delimiter=delimiter)
          self.source_data = {"title": source_data[0].tolist(),
                              "data": source_data[1:]}
  
          cell_format_title = self.workbook.add_format({'bold': True,
                                                        'font_name': u'等线',
                                                        'bg_color': '#c5d9f1',
                                                        'rotation': 45})
          cell_format = self.workbook.add_format({'bold': False,
                                                  'font_name': u'等线',
                                                  'num_format': 0})
  
          worksheet = self.workbook.add_worksheet(sheet)
          worksheet.write_row('A1', self.source_data['title'], cell_format_title)
  
          _, col_num = self.source_data['data'].shape
          for i in range(col_num):
              try:
                  data_array = self.source_data['data'][:, i].astype(float)
              except ValueError:
                  data_array = self.source_data['data'][:, i]
  
              worksheet.write_column(1, i, data_array.tolist(), cell_format)
docs: Function:
              Save original data into specific sheet, and try to translate data to float type
          Input:
              sheet: Must be a non exists sheet
              source: File path of source