appearance is not working when adding on type text field

[naiyyar]

Hi,
Below is my code. It's not setting the detail_font to bold. i have tried in 3 different ways but not setting textfield detail_font to bold.

def form_data
  [{
      cells: [{
                title: '',
                name: :title,
                type: :text,
                value: task['title'],
                appearance: {
                    font: UIFont.fontWithName('HelveticaNeue-Bold', size: 16.0),
                    detail_font: UIFont.fontWithName('HelveticaNeue-Bold', size: 16.0),
                    #font: UIFont.fontWithName('Arial-BoldMT', size: 16.0),
                    #detail_font: UIFont.fontWithName('Arial-BoldMT', size: 16.0),
                   # font: UIFont.boldSystemFontOfSize(18),
                   # detail_font: UIFont.boldSystemFontOfSize(18)
              }
       }]
  }]
end

How can i do that?
Thanks