import timeit
import struct
from struct import unpack

def f(x, unpack=struct.unpack):
    return unpack('<i', x)

def g(x):
    return unpack('<i', x)

def h(x, unpack=struct.Struct('<i').unpack):
    return unpack(x)

print(min(timeit.repeat('u(%r)' % b'abcd', setup='from __main__ import f as u')))
print(min(timeit.repeat('u(%r)' % b'abcd', setup='from __main__ import g as u')))
print(min(timeit.repeat('u(%r)' % b'abcd', setup='from __main__ import h as u')))