code: def fetch_value(self, select, table_name, where=None, extra=None):
          
  
          try:
              self.verify_table_existence(table_name)
          except TableNotFoundError as e:
              logger.debug(e)
              return None
  
          result = self.execute_query(
              Select(select, table_name, where, extra), logging.getLogger().findCaller()
          )
          if result is None:
              return None
  
          fetch = result.fetchone()
          if fetch is None:
              return None
  
          return fetch[0]
docs: Fetch a value from the table. Return |None| if no value matches
          the conditions, or the table not found in the database.
  
          :param str select: Attribute for SELECT query
          :param str table_name: Table name of executing the query.
          :param where: |arg_select_where|
          :type where: |arg_where_type|
          :return: Result of execution of the query.
          :raises simplesqlite.NullDatabaseConnectionError:
              |raises_check_connection|
          :raises simplesqlite.OperationalError: |raises_operational_error|