<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _slugify_title(self):
 """Slugify the Entry title, but ensure it's less than the maximum number of characters. This method also ensures that a slug is unique by appending a timestamp to any duplicate slugs. """

        # Restrict slugs to their maximum number of chars, but don't split mid-word
        self.slug = slugify(self.title)
        while len(self.slug) > 255:
            self.slug = '-'.join(self.slug.split('-')[:-1])

        # Is the same slug as another entry?
        if Entry.objects.filter(slug=self.slug).exclude(id=self.id).exists():
            # Append time to differentiate.
            self.slug = self._insert_timestamp(self.slug)