old_contents: # A romanesco script to convert a slide to a TIFF using vips.
  import subprocess
  import os
  
  out_path = os.path.join(_tempdir, out_filename)
  
  convert_command = (
      'vips',
      'tiffsave',
      '"%s"' % in_path,
      '"%s"' % out_path,
      '--compression', 'jpeg',
      '--Q', '90',
      '--tile',
      '--tile-width', '256',
      '--tile-height', '256',
      '--pyramid',
      '--bigtiff'
  )
  
  proc = subprocess.Popen(convert_command)
  proc.wait()
  
  if proc.returncode:
      raise Exception('VIPS process failed (rc=%d).' % proc.returncode)
  
new_contents: # A romanesco script to convert a slide to a TIFF using vips.
  import subprocess
  import os
  
  out_path = os.path.join(_tempdir, out_filename)
  
  convert_command = (
      'vips',
      'tiffsave',
      '"%s"' % in_path,
      '"%s"' % out_path,
      '--compression', 'jpeg',
      '--Q', '90',
      '--tile',
      '--tile-width', '256',
      '--tile-height', '256',
      '--pyramid',
      '--bigtiff'
  )
  
  proc = subprocess.Popen(convert_command)
  proc.wait()
  
  if proc.returncode:
      raise Exception('VIPS command failed (rc=%d): %s' % (
          proc.returncode, ' '.join(convert_command)))
  
subject: Print command in failure case