class CategoryWidget(forms.CheckboxSelectMultiple):

    def render(self, name, value, attrs=None, choices=()):
        final_attrs = self.build_attrs(attrs, name=name)
        output = [u'<ul>']
        print 1, locals()

        def render_list(choices):
            print 2, locals()
            for i, (option_value, option_label, children) in enumerate(choices):
                final_attrs = dict(final_attrs, id='%s_%s' % (attrs['id'], i))
                label_for = u' for="%s"' % final_attrs['id']
                cb = forms.CheckboxInput(final_attrs, check_test=lambda value: value in str_values)
                option_value = force_unicode(option_value)
                rendered_cb = cb.render(name, option_value)
                option_label = conditional_escape(force_unicode(option_label))
                output.append(u'<li><label%s>%s %s</label></li>' % (label_for, rendered_cb, option_label))        

        render_list(chain(self.choices, choices))
        output.append(u'</ul>')
        return mark_safe(u'\n'.join(output))

def g():
    a = [2]
    print locals()

    def f():
        print locals()
        a.append(a)
        print locals()
    f()

g()

def g():
    a = [2]
    print locals()
    
    def f():
        print locals()
        a = 3
        print locals()

    f()

g()

def g():
    a = [2]
    def f():
        print a
    f()
g()

def g():
    a = [2]
    def f():
        del a
    f()
g()

def foo():
    var1 = []
    var2 = []
    print 1, locals()

    def closure1():
        print 2, locals()
        var1.append(1)
        var2 = []

    def closure2():
        print 3, locals()
        var1 = []
        var2.append(1)

    closure1()
    closure2()

foo()