我需要在用户输入列表中查找最小值、最大值、范围和平均值，但不能使用内置函数来查找它们

def find_min_value(lst):
    min_value = lst[0]
    for num in lst:
        if num < min_value:
            min_value = num
    return min_value

def find_max_value(lst):
    max_value = lst[0]
    for num in lst:
        if num > max_value:
            max_value = num
    return max_value

def find_range(lst):
    min_value = find_min_value(lst)
    max_value = find_max_value(lst)
    return max_value - min_value

def find_average(lst):
    sum_value = 0
    count = 0
    for num in lst:
        sum_value += num
        count += 1
    average = sum_value / count
    return average