I have trouble executing a python in a terminal.

My file name is `ex18.py` and I am using python 3.7.

To run my function I write the following on terminal:

`$ python3.7 ex18.py`

This is how my code looks like:

```
def print_two(*args):
    arg1, arg2 = args
    print(f"arg1: {arg1}, arg2: {arg2}")

def print_two_again(arg1, arg2):
    print(f"arg1: {arg1}, arg2: {arg2}")

def print_one(arg1):
    print(f"arg1: {arg1}")

def print_none():
    print("I got nothing.")

    print_two("Zed", "Shaw")
    print_two_again("Zed","Shaw")
    print_one("First!")
    print_none()

```

I expect to see the following when I run it on terminal:

```
arg1: Zed, arg2: Shaw
arg1: Zed, arg2: Shaw
arg1: First!
I got nothing.

```