dict.update

gistfile1.txt

>>> import code
>>> import dis
>>> def func():
...   d = {}
...   d.update({'a': 2, 'b':3})
...
>>> dis.dis(func.__code__)
  2           0 BUILD_MAP                0
              3 STORE_FAST               0 (d)

  3           6 LOAD_FAST                0 (d)
              9 LOAD_ATTR                0 (update)
             12 BUILD_MAP                2
             15 LOAD_CONST               1 (2)
             18 LOAD_CONST               2 ('a')
             21 STORE_MAP
             22 LOAD_CONST               3 (3)
             25 LOAD_CONST               4 ('b')
             28 STORE_MAP
             29 CALL_FUNCTION            1 (1 positional, 0 keyword pair)
             32 POP_TOP
             33 LOAD_CONST               0 (None)
             36 RETURN_VALUE
>>> def bunc():
...   d = {}
...   d['a'] = 2
...   d['b'] = 3
...
>>> dis.dis(bunc.__code__)
  2           0 BUILD_MAP                0
              3 STORE_FAST               0 (d)

  3           6 LOAD_CONST               1 (2)
              9 LOAD_FAST                0 (d)
             12 LOAD_CONST               2 ('a')
             15 STORE_SUBSCR

  4          16 LOAD_CONST               3 (3)
             19 LOAD_FAST                0 (d)
             22 LOAD_CONST               4 ('b')
             25 STORE_SUBSCR
             26 LOAD_CONST               0 (None)
             29 RETURN_VALUE
>>>