code: def append(self, vals: list, index=None):
          
          try:
              self.df = self.df.loc[len(self.df.index)] = vals
          except Exception as e:
              self.err(e, self.append, "Can not append row")
              return
          self.ok("Row added to dataframe")
docs: Append a row to the main dataframe
  
          :param vals: list of the row values to add
          :type vals: list
          :param index: index key, defaults to None
          :param index: any, optional
  
          :example: ``ds.append([0, 2, 2, 3, 4])``