Вызов значения из другой функции

def devi(input_list, mean_val): #deviation
 
    for number in input_list:
 
        variance = sum((number - mean_val)**2)/len(input_list)
 
    devi_val = variance**0.5
 
    return devi_val
 
def mean(input_list): #average
 
    sum = 0
    mean_val = 0
    for number in input_list:
        sum += int(number)
 
    mean_val = sum/len(input_list)
 
    return mean_val
 
def med(input_list): #median
 
    test_list = sorted(input_list)
    N = len(test_list)//2
 
    if len(test_list)%2 == 0:
        med_val = int(test_list[int(N)]+test_list[int(N-1)])/2
    else:
        med_val = input_list[N]
 
    return med_val
 
def min_max(input_list): #min max values
 
    max_val = max(input_list)
 
    min_val = min(input_list)
 
    return max_val, min_val
 
def main():
 
    input_list = [] #initial list is empty.
    print("Enter seawater levels in centimeters one per line.")
    print("End by entering an empty line.")
 
    index = 1
    number = None
    while number != "":
        number = input()
        input_list.append(number)
        if number == "" and index == 1:
            print("Error: At least two measurements must be entered!")
        elif number == "" and index == 2:
            print("Error: At least two measurements must be entered!")
            break
        elif number == "" and index > 2:
            input_list.remove(number)
 
        index += 1
 
    print(max(input_list))
    print(min(input_list))
    print(med(input_list))
    print(mean(input_list))
    print(devi(input_list))
 
if __name__ == "__main__":
      main()

def mean(values):
    return sum(values) / len(values)
 
 
def median(values):
    center_index = len(values) // 2
    if len(values) % 2:
        return sorted(values)[center_index]
    return sum(sorted(values)[center_index - 1:center_index + 1]) / 2
 
 
def deviation(values):
    mean_value = mean(values)
    dispersion = sum((mean_value - i) ** 2 for i in values) / len(values)
    return dispersion ** 0.5
 
 
def main():
    data = []  # initial list is empty.
    print("Enter seawater levels in centimeters one per line.")
    print("End by entering an empty line.")
 
    while True:
        user_input = input()
        if user_input == "":
            if len(data) >= 2:
                break
            else:
                print("Error: At least two measurements must be entered!")
                continue
        try:
            data.append(float(user_input))
        except ValueError:
            print("Error: Not a number")
 
    print(f"Maximum value = {max(data)}")
    print(f"Minimum value = {min(data)}")
    print(f"Median value = {median(data)}")
    print(f"Mean value = {mean(data)}")
    print(f"Deviation = {deviation(data)}")
 
 
if __name__ == "__main__":
    main()