No method error when trying to use FlatUIKit's configureFlatButtonsWithColor https://github.com/Grouper/FlatUIKit

home_screen.rb

# Notes:
#
# FlatUIKit: https://github.com/Grouper/FlatUIKit
# 
# Their Example:

# [UIBarButtonItem configureFlatButtonsWithColor:[UIColor peterRiverColor]
#                               highlightedColor:[UIColor belizeHoleColor]
#                                   cornerRadius:3];
#
#
# I am using ProMotion and Sugarcube... I am able to use FlatUIKit to style the navigation bar
# but I can't for the life of me get it to style the buttons. I think I am calling the method
# correctly, but it toally fails. I am not sure what I'm doing wrong, or even where to look! :(
#
# me = rubymotion noob
#

class HomeScreen < ProMotion::Screen
  title "HomeScreen"

  def will_appear
    
    # No Method Error `configureFlatButtonsWithColor`
    UIBarButtonItem.appearance.configureFlatButtonsWithColor(UIColor.whiteColor, highlightedColor: "#2DA5FA".uicolor, cornerRadius: 2)
    
    @nav_bar = UINavigationBar.appearance
    # This works! Totally styles the navigation bar with FlatUIKIT
    @nav_bar.configureFlatNavigationBarWithColor("#1FA1F8".uicolor)
    @nav_bar.setTitleTextAttributes({
        UITextAttributeTextShadowColor => UIColor.colorWithWhite(0.0, alpha:0.0),
        UITextAttributeTextColor => UIColor.whiteColor
    })

    navigationItem.rightBarButtonItem = UIBarButtonItem.alloc.initWithTitle("Login", style: UIBarButtonItemStylePlain, target:self, action:'login')
    
    
    set_attributes self.view, {
      backgroundColor: UIColor.whiteColor
    }
  end

  def login
      puts "Login button clicked"
  end
end