a.py

def angka():
    return 10

print angka()

b.py

def kali_sepuluh(func):
    def inner_func():
        hasil = func()
        return 10 * hasil
    return inner_func

@kali_sepuluh
def angka():
    return 10

def angka_juga():
    return 20
angka_juga_decorated = kali_sepuluh(angka_juga)


print angka()
print angka_juga()
print angka_juga_decorated()

c.py

def api(func):
    def inner(request):
        hasil = func(request)
        return HttpResponse(json.dumps(hasil))
    return inner

@api
def daftar_angka(request):
    hasil = ['satu', 'dua', 'tiga']
    return hasil

d.py

def int_only(func):
    def cek_input(*args):
        args_filtered = []
        for arg in args:
            if type(arg) == int:
                args_filtered.append(arg)
        return func(*args_filtered)
    return cek_input

@int_only
def cetak(*args):
    print 'Cetak:'
    for arg in args:
        print '-', arg

cetak(1, 2, 'tiga', 'empat', 5, 6, object(), None, 'sembilan', 10)

e.py

def str_only(func):
    def cek_output(*args):
        hasil = func(*args)
        filtered = []
        for item in hasil:
            if type(item) == str:
                filtered.append(item)
        return filtered
    return cek_output

@str_only
def apalah():
    return ['satu', 2, 3, 'empat', None, 6, 'tujuh']

print apalah()