def get(self, id, pk='id', deleted=False):
        try:
            if pk == 'id':
                id = int(id)
            if deleted:
                spec = {pk: id}
            else:
                spec = {pk: id, 'data': {'$exists': 1}}
            fields = {'_id': 0}
            row = self.db.docs.find_one(spec, fields)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return Document(**row)
        raise NotFoundError('%s %s not found' % (pk, id))
def render(self, context):
        try:
            if self.params:
                params = template.Variable(self.params).resolve(context)
            else:
                params = {}

            # try matching an address string literal
            email_literal = self.email.strip().lower()
            if EMAIL_RE.match(email_literal):
                email = email_literal
            # treat as a variable
            else:
                email = template.Variable(self.email).resolve(context)
        except template.VariableDoesNotExist:
            return ''

        # now, we generate the gravatar url
        return _build_gravatar_url(email, params)