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    Lab 3, Part 1: print, return, and None
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# Lab 3, Part 1: print, return, and None

Summary

- `print` causes characters to be displayed in the shell (the bottom pane of your Thonny window)
- `return` specifies the result of the function invocation
- a function without an explicit `return` statement returns the special `None` value (which Python typically does not print)

[Here is the worksheet as a google doc](https://docs.google.com/document/d/1Si5WZQ278a9Zz9Jj6ecvK7rzaLf2c5wIIChIcCTUp1U/edit?usp=sharing)
Open the document, then File -> Make a Copy. Then you can edit your copy with your answers.

Examine the following functions. Which are **fruitful** and which are **None** functions?


```py
def hello(x):
    print('--', x, '--')

def square(x):
    return x * x

def showSquare(num):
    print('The argument of square is ' + str(num))
    return square(num)

```

<!--
Fall 2020, removed squareTest from worksheet to speed things along

def squareTest(a):
    print('Square of ' + str(a) + ' is ' + str(square(a)))
-->

Predict the outcome of the invocations below:



```py
>>> hello('froggy')

>>> print(hello('bunny'))


```

```py
>>> square(3) + square(4)

```

```py
>>> square(square(3))

```

```py
>>> showSquare(5)

```

```py
>>> showSquare(3) + showSquare(4)

```

```py
>>> hello('frog') + hello('toad')

```


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