9 Bug log

Your bug log is where you keep a record of bugs you encountered while programming. We’ll start you off with one example bug. Then, keep adding to to your log with the template below.

9.1 Bug #1 (`NoneType`)

Code

def double(x):
   x * 2
4 + double(3)

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[1], line 3
      1 def double(x):
      2    x * 2
----> 3 4 + double(3)

TypeError: unsupported operand type(s) for +: 'int' and 'NoneType'

Field	Description
Symptom	`TypeError: unsupported operand type(s) for +: 'int' and 'NoneType'`
Proximal Cause	data fault: `double(3)` has the value `None`.
Root Cause	`double(x)` returns value `None`
Fix	Added the missing return statement to the function.

9.2 Bug #2

Relevant code and context goes here. You may use code formatting in Markdown or create a code cell for the example.

Field	Description
Symptom	Fill this in.
Proximal Cause	Fill this in.
Root Cause	Fill this in.
Fix	Fill this in.