>>> browser.addHeader('Authorization', 'Basic carlos@canonical.com:test')
  >>> browser.open(
  ...     'http://localhost/distros/ubuntu/hoary/+source/evolution/+pots/evolution-2.2/es/+translate')
  >>> browser.url
  'http://localhost/distros/ubuntu/hoary/+source/evolution/+pots/evolution-2.2/es/+translate'
  >>> browser.getControl(name='msgset_139_es_translation_0').value = 'Foo\r\nBar'
  >>> browser.getControl(name='msgset_139_es_translation_0').value
  'Foo\r\nBar'
  >>> browser.getControl(name='submit_translations').click()
  >>> browser.getLink('Previous').click()
  >>> browser.getControl(name='msgset_139_es_translation_0').value
  'Foo\r\nBar'