Edit and save same xml file ruby

I have written a code that remove comments on xml file, how can i save it as an xml file again. Currently i read the xml file a text file. When i run this code on the console it outputs the xml content, but on the newexample.xml it prints out this : **#<File:0x00000002b8be40>**

here is the code

file = File.open('C:/ruby/example.xml','r+') do |file|
    file.each {|line| line.gsub(/^\s\W*\s$/, " ")}

end


 File.open("newexample.xml","w") do |f|
    f.write file 
end