定义draw_histogram（）函数，该函数通过Python字典作为参数传递

Question

when run my code, it always shows nothing. I am so confused as to what wrong about my code. Here is what I coded:

def draw_histogram(histogram_dict):
    all_keys = list(histogram_dict.keys())
    all_keys.sort()
    for key in all_keys:
       stars = "*" * histogram_dict[key] 
       print(key, ":", stars)
def test_draw_histogram():
    print("1.")
    draw_histogram({'a': 2, 'c': 7, 'b': 5})
    print()

    print("2.")
    draw_histogram({'a': 0, 'c': 5, 'b': 7, 'f': 0})

And the output should be something like this:

 a: **

 b: *****

 c: *******

Answer 1

def draw_histogram(histogram_dict):
    all_keys = list(histogram_dict.keys())
    all_keys.sort()
    for key in all_keys:
        stars = "*" * histogram_dict[key]
        print(key, ":", stars)

def test_draw_histogram():
    print("1.")
    draw_histogram({'a': 2, 'c': 7, 'b': 5})
    print("\n")
    print("2.")
    draw_histogram({'a': 0, 'c': 5, 'b': 7, 'f': 0})

test_draw_histogram()

You need to call the function you've just defined.