<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def load_table(self, table_name):
 """Load a table. This will fail if the tables does not already exist in the database. If the table exists, its columns will be reflected and are available on the :py:class:`Table <dataset.Table>` object. Returns a :py:class:`Table <dataset.Table>` instance. :: table = db.load_table('population') """

        table_name = normalize_table_name(table_name)
        with self.lock:
            if table_name not in self._tables:
                self._tables[table_name] = Table(self, table_name)
            return self._tables.get(table_name)