def page_section(name, section_class, identifier)
      define_method(name) do
        platform.page_for(identifier, section_class)
      end
    end
def page_section(name, section_class, identifier)
      define_method(name) do
        platform.page_for(identifier, section_class)
      end
    end
adds a method to return a page object rooted at an element

 @example
   page_section(:navigation_bar, NavigationBar, :id => 'nav-bar')
   # will generate 'navigation_bar'

 @param [Symbol] the name used for the generated methods
 @param [Class] the class to instantiate for the element
 @param [Hash] identifier how we find an element.