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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def commit(self):
 """ Commit changes to disk if attached. This method helps normalize the interface for detached and attached tables and makes writing attached tables a bit more efficient. For detached tables nothing is done, as there is no notion of changes, but neither is an error raised (unlike with :meth:`write`). For attached tables, if all changes are new records, the changes are appended to the existing file, and otherwise the whole file is rewritten. """

        if not self.is_attached():
            return
        changes = self.list_changes()
        if changes:
            indices, records = zip(*changes)
            if min(indices) > self._last_synced_index:
                self.write(records, append=True)
            else:
                self.write(append=False)