How to use the jinja2.utils.soft_unicode function in Jinja2

def do_title(s):
    """Return a titlecased version of the value. I.e. words will start with
    uppercase letters, all remaining characters are lowercase.
    """
    rv = []
    for item in re.compile(r'([-\s]+)(?u)').split(soft_unicode(s)):
        if not item:
            continue
        rv.append(item[0].upper() + item[1:].lower())
    return ''.join(rv)

def do_capitalize(s):
    """Capitalize a value. The first character will be uppercase, all others
    lowercase.
    """
    return soft_unicode(s).capitalize()

def do_upper(s):
    """Convert a value to uppercase."""
    return soft_unicode(s).upper()

{{ "Hello World"|replace("Hello", "Goodbye") }}
            -> Goodbye World

        {{ "aaaaargh"|replace("a", "d'oh, ", 2) }}
            -> d'oh, d'oh, aaargh
    """
    if count is None:
        count = -1
    if not eval_ctx.autoescape:
        return text_type(s).replace(text_type(old), text_type(new), count)
    if hasattr(old, '__html__') or hasattr(new, '__html__') and \
       not hasattr(s, '__html__'):
        s = escape(s)
    else:
        s = soft_unicode(s)
    return s.replace(soft_unicode(old), soft_unicode(new), count)

{{ "Hello World"|replace("Hello", "Goodbye") }}
            -> Goodbye World

        {{ "aaaaargh"|replace("a", "d'oh, ", 2) }}
            -> d'oh, d'oh, aaargh
    """
    if count is None:
        count = -1
    if not eval_ctx.autoescape:
        return text_type(s).replace(text_type(old), text_type(new), count)
    if hasattr(old, '__html__') or hasattr(new, '__html__') and \
       not hasattr(s, '__html__'):
        s = escape(s)
    else:
        s = soft_unicode(s)
    return s.replace(soft_unicode(old), soft_unicode(new), count)

def do_capitalize(s):
    """Capitalize a value. The first character will be uppercase, all others
    lowercase.
    """
    return soft_unicode(s).capitalize()

{{ "Hello World"|replace("Hello", "Goodbye") }}
            -> Goodbye World

        {{ "aaaaargh"|replace("a", "d'oh, ", 2) }}
            -> d'oh, d'oh, aaargh
    """
    if count is None:
        count = -1
    if not eval_ctx.autoescape:
        return text_type(s).replace(text_type(old), text_type(new), count)
    if hasattr(old, '__html__') or hasattr(new, '__html__') and \
       not hasattr(s, '__html__'):
        s = escape(s)
    else:
        s = soft_unicode(s)
    return s.replace(soft_unicode(old), soft_unicode(new), count)

def do_trim(value):
    """Strip leading and trailing whitespace."""
    return soft_unicode(value).strip()

def do_format(value, *args, **kwargs):
    """
    Apply python string formatting on an object:

    .. sourcecode:: jinja

        {{ "%s - %s"|format("Hello?", "Foo!") }}
            -> Hello? - Foo!
    """
    if args and kwargs:
        raise FilterArgumentError('can\'t handle positional and keyword '
                                  'arguments at the same time')
    return soft_unicode(value) % (kwargs or args)

def do_lower(s):
    """Convert a value to lowercase."""
    return soft_unicode(s).lower()