Write a program that produces all possible sub-dictionaries from a dictionary, and stores them in a list. For instance, if the dictionary is {"a": 1, "b": 2}, the program produces [{}, {"a": 1}, {"b": 2}, {"a": 1, "b": 2}] (the ordering of the list does not matter). Again, use the itertools module.

Assignment

Write a function sub_dictionaries that takes one dict and returns a list containing all its sub-dictionaries: every dictionary that can be formed by keeping some subset of the key/value pairs of the given dictionary. This includes the empty dictionary and the dictionary itself. The order of the sub-dictionaries in the returned list does not matter, and neither does the order of the key/value pairs within each sub-dictionary.

Example

>>> sub_dictionaries({"a": 1, "b": 2})
[{}, {'a': 1}, {'b': 2}, {'a': 1, 'b': 2}]

>>> sorted(sorted(sub.items()) for sub in sub_dictionaries({"x": 3, "y": 8}))
[[], [('x', 3)], [('x', 3), ('y', 8)], [('y', 8)]]