I use 3 lists to store field name, its value and score. If field name is already added to according list, then I just need to update other 2 lists. If it is not there, then I need to add it. I do the following:user = User.get_by_key_name(user_key_name)if user:    field_names = user.field_names    field_values = user.field_values    field_scores = user.field_scores    if field_name in user.field_names:        # field_names[field_index] = field_name        field_index = user.field_names.index(field_name)        field_values[field_index] = field_value        field_scores[field_index] = field_score    else:        field_names.append(field_name)        field_values.append(field_value)        field_scores.append(field_score)    user.field_names = field_names    user.field_values = field_values     user.field_scores = field_scores    user.put()Is it correct approach?
How to verify if value already added to the list and if so, then update the value?
python;google app engine