## Issue There are two places using invalid field types (`map<string, unsigned int>`) in https://github.com/facebook/facebook-ruby-ads-sdk/blob/master/lib/facebook_ads/ad_objects/ad.rb#L104 and https://github.com/facebook/facebook-ruby-ads-sdk/blob/master/lib/facebook_ads/ad_objects/ad_set.rb#L129 so it doesn't get found in https://github.com/facebook/facebook-ruby-ads-sdk/blob/master/lib/facebook_ads/field_types.rb#L44 when data for the field returned, and it returns as string i.e.) so when it returns hash object `{ 'foo' => 'bar' }`, it will be returned as `"{\"foo\" => \"bar\" }"` as a string