Write a function named switch_pairs that accepts a list of strings as a parameter and switches the order of pairs of values in the list.
Your function should swap the order of the first two values, then switch the order of the next two, and so on.
For example, if the list stores:
a = ["a", "bb", "c", "ddd", "f", "ee", "g"]
switch_pairs(a)
Your function should switch the first pair ("a", "bb"), the second pair ("c", "ddd") and the third pair ("ee", "f"), to yield this list:
["bb", "a", "ddd", "c", "f", "ee", "g"]
If there are an odd number of values, the element is not moved.
You may assume that the list is not None and that no element of the list is None.
