bot with functions

# Programming 101: An introduction to Python for Educators
# on Future Learn, and Raspberry Pi Foundation

# In this program we are creating a bot more intelligent than its creator.
# option two: we will use functions in this version

# a function to calculate: add, subtract, multiply, divide
def do_calculation():
    print("lets " + command + " some numbers")
    input1 = input("Number 1> ")
    input2 = input("Number 2> ")
    number1 = int(input1)
    number2 = int(input2)
    if command == "add":
        result = number1 + number2
        operator = " + "
    elif command == "subtract":
        result = number1 - number2
        operator = " - "
    elif command == "multiply":
        result = number1 * number2
        operator = " * "
    elif command == "divide":
        if number2 != 0:
            result = number1/number2
            operator = " / "
    if command == "divide" and number2 == 0:
        print("Warning: Undefined, division by zero is undefined")
    else:
        output = str(result)
        print("Answer: " + input1 + operator + input2 + " = " + output)

# a function to calculate: total, average
def do_statistics():
    how_many = input("How many numbers> ")
    how_many = int(how_many)
    total = 0
    for number_count in range(how_many):
        number = input("Enter number " + str(number_count) + "> ")
        total = total + int(number)
    if command == "total":
        result = total
    elif command == "average":
        result = total / how_many
    print("Answer: " + command + " " + str(result))

finished = False
while finished == False:
    print("**********************************************")
    print('Hi, I am Marvin, your personal bot.')
    # ask the user to enter their name
#    users_name = input("What is your name?  ")
    # print a message including the name
#    print('Welcome ' + users_name )
    # ask for the user's wishes and fantacies
    Things_I_Do=['add','subtract','multiply','divide','total','average','shop','bye']
    print("These are the tasks I can perform: ", Things_I_Do)
    command = input("How can I help? ")
    if command == "add":
        do_calculation()
    elif command == "subtract":
        do_calculation()
    elif command == "multiply":
        do_calculation()
    elif command == "divide":
        do_calculation()
    elif command == "total":
        do_statistics()
    elif command == "average":
        do_statistics()
    elif command == "shop":
        shopping = []
        how_many = input("how many items of shopping do you have? ")
        how_many = int(how_many)
        for item_number in range(how_many):
            item = input("what is item number " + str(item_number+1) + "? ")
            shopping.append(item)
        print("Shopping List: ", shopping)
        count = 0
        for item in shopping:
            print(item)
            count = count +1
        print("you have ", count, " items in your shopping list")
    elif command == "bye":
        finished = True
    else:
        print("sorry I dont understand")