title: Python Global File
body: <p>How can I write to a global file inside of a function?</p>
  
  <p>Example:</p>
  
  <pre><code>output_file=open("output_file_name.txt", "w")
  
  def write_to_file:    
      global output_file    
      output_file.write('something')
  
  write_to_file()
  
  output_file.close()
  </code></pre>
  
  <p>The code above is not working. It says "ValueError: I/O operation on closed file" 
  Any ideas?</p>