In these examples, Python merges dictionary keys in the order listed in the expression, overwriting duplicates from left to right.
# How to merge two dictionaries
# in Python 3.5+
>>> x = {'a': 1, 'b': 2}
>>> y = {'b': 3, 'c': 4}
>>> z = {**x, **y}
>>> z
{'c': 4, 'a': 1, 'b': 3}
# In Python 2.x you could
# use this:
>>> z = dict(x, **y)
>>> z
{'a': 1, 'c': 4, 'b': 3}