code: def _read_as_table(self):
          
          rows = list()
  
          for row in self._rows:
              rows.append([row[i].get() for i in range(self.num_of_columns)])
  
          return rows
docs: Read the data contained in all entries as a list of
          lists containing all of the data
  
          :return: list of dicts containing all tabular data