def postSave(self, parsed):
    extra_columns = {}

    for org in self.data.mentor_for:
      for column in org.proposal_extra:
        extra_columns.setdefault(org.key.id(), []).append(column)

    for _, properties in parsed.iteritems():
      if 'org_key' not in properties or 'full_proposal_key' not in properties:
        logging.warning("Missing key in '%s'", properties)
        continue

      org_key_name = properties.pop('org_key')
      proposal_key = properties.pop('full_proposal_key')

      valid_columns = set(extra_columns.get(org_key_name, []))
      remove_properties = []

      for key, value in properties.iteritems():
        if key not in valid_columns:
          logging.warning("Invalid property '%s'", key)
          remove_properties.append(key)
        try:
          cleaning.sanitize_html_string(value)
        except Exception:
          remove_properties.append(key)

      for prop in remove_properties:
        properties.pop(prop)

      def update_proposal_txn():
        proposal = db.get(db.Key(proposal_key))

        if not proposal:
          logging.warning("Invalid proposal_key '%s'", proposal_key)
          return

        data = {}

        if proposal.extra:
          # we have to loads in the txn, should be fast enough
          data = json.loads(proposal.extra)

        data.update(properties)

        proposal.extra = json.dumps(data)
        proposal.put()

      db.run_in_transaction(update_proposal_txn)

    return True