'A decorator that is used to register custom template filter.
You can specify a name for the filter, otherwise the function
name will be used. Example::
@app.template_filter()
def reverse(s):
return s[::-1]
:param name: the optional name of the filter, otherwise the
function name will be used.'

@setupmethod
def template_filter(self, name=None):

    def decorator(f):
        self.add_template_filter(f, name=name)
        return f
    return decorator
