def _django_boolean(boolean):
    """Render a string suitable for use in a Django form.

    Django's `BooleanField` understands "true", "false", "1", "0", "t", and
    "f" as valid form values, but the widget `CheckboxInput` that is used by
    `BooleanField` by default gets a shot at converting the form input first.
    It inexplicably has different rules. See in `value_from_datadict`:

      values = {'true': True, 'false': False}
      if isinstance(value, six.string_types):
          value = values.get(value.lower(), value)
      return bool(value)

    Sigh.
    """
    return 'true' if boolean else 'false'
