Removed support is_safe and needs_autoescape as function attributes.

    # when multiple decorators are applied).

    _dec._decorated_function = getattr(func, '_decorated_function', func)

    for attr in ('is_safe', 'needs_autoescape'):

        if hasattr(func, attr):

            import warnings

            warnings.warn("Setting the %s attribute of a template filter "

                          "function is deprecated; use @register.filter(%s=%s) "

                          "instead" % (attr, attr, getattr(func, attr)),

                          DeprecationWarning)

            setattr(_dec, attr, getattr(func, attr))

    return wraps(func)(_dec)

   handle the auto-escaping issues and return a safe string, the

   ``is_safe`` flag won't change anything either way.

.. versionchanged:: 1.4

``is_safe`` and ``needs_autoescape`` used to be attributes of the filter

function; this syntax is deprecated.

.. code-block:: python

    @register.filter

    def myfilter(value):

        return value

    myfilter.is_safe = True

.. code-block:: python

    @register.filter

    def initial_letter_filter(text, autoescape=None):

        # ...

        return mark_safe(result)

    initial_letter_filter.needs_autoescape = True

.. _filters-timezones:

Filters and time zones