Define a function that takes an argument. Call the function. Identify what code is the argument and what code is the parameter.

To define a function that takes an argument, you can follow these steps:

1. Start by using the keyword "def" to indicate that you are defining a function.
2. Give your function a name that is descriptive of its purpose.
3. Inside the parentheses, specify a parameter that will be used to pass in the argument.
4. Write the code block for the function, which will contain the instructions or operations to be performed.
5. Call the function by using its name followed by parentheses, and provide an argument within the parentheses.

For example, let's define a function called "greet" that takes a name as an argument:

def greet(name):
    print("Hello, " + name + "!")

greet("John")

In this example, the code "name" is the parameter, as it is specified in the function definition. The code "John" is the argument, as it is passed into the function when calling it.