docs: def GetFilename(multiple=False, sep='|', **kwargs):
      """Prompt the user for a filename.
      
      This will raise a Zenity File Selection Dialog. It will return a list with 
      the selected files or None if the user hit cancel.
      
      multiple - True to allow the user to select multiple files.
      sep - Token to use as the path separator when parsing Zenity's return 
            string.
      kwargs - Optional command line parameters for Zenity such as height,
               width, etc."""
  
      args = []
      if multiple:
          args.append('--multiple')
      if sep != '|':
          args.append('--separator=%s' % sep)
      
      for generic_args in kwargs_helper(kwargs):
          args.append('--%s=%s' % generic_args)
  
      p = run_zenity('--file-selection', *args)
  
      if p.wait() == 0:
          return p.stdout.read()[:-1].split('|')