merging two dictionaries

[snippsat]

If someone wonder about **,so is it PEP 448 and work for 3.5-->.

Where 'two' gone?

The task here was not to retaining values,as mention dictionary can not have duplicate keys.
If want to retaining values when there is key collisions use defaultdict.

>>> from itertools import chain
... from collections import defaultdict
... d1 = {1:'one',2:'two'}
... d2 = {2:'deux',3:'trois'}
... d3 = defaultdict(list)
... for k, v in chain(d1.items(), d2.items()):
...     d3[k].append(v)

>>> d3
defaultdict(<class 'list'>, {1: ['one'], 2: ['two', 'deux'], 3: ['trois']})