class Hash

def to_plist(options={})

convert a hash to plist format 
def to_plist(options={})
  options[:plist_format] ||= CFPropertyList::List::FORMAT_BINARY
  plist = CFPropertyList::List.new
  plist.value = CFPropertyList.guess(self, options)
  plist.to_str(options[:plist_format])
end