1.
a. This is a test, it is only a test.
b. This is a test of: test

2.
def filter_dict(my_dict, minimum, maximum = None):
    for key in my_dict.keys():
        if my_dict[key] <= minimum:
            del my_dict[key]
        elif maximum != None and my_dict[key] >= maximum:
            del my_dict[key]