>>> from timeit import timeit >>> timeit("a = {'a': 1, 'b': 2}") 0.424... >>> timeit("a = dict(a = 1, b = 2)") 0.889...
>>> import dis >>> dis.dis("{ }") 0 <123> 32032 >>> dis.dis("dict()") 0 LOAD_CONST 25449 (25449) 3 LOAD_GLOBAL 10536 (10536) >>>