<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def collection(self):
 """Return the redis-collection instance."""

        if not self.include_collections:
            return None
        ctx = stack.top
        if ctx is not None:
            if not hasattr(ctx, 'redislite_collection'):
                ctx.redislite_collection = Collection(redis=self.connection)
            return ctx.redislite_collection