Import is Important Tutorial

Warm Up Exercises

Learning Objectives

By the end of this lab, you will be able to:

1. Write correct import statements using both absolute and relative import syntax
2. Refactor code into separate modules while maintaining proper import relationships between files
3. Organize Python code using packages with __init__.py files
4. Use __init__.py files to control package initialization and automatic imports
5. Apply relative imports within package hierarchies
6. Diagnose and resolve common import errors including NameError, ImportError, AttributeError, and ModuleNotFoundError

Setup Instructions

1. Follow these setup instructions, then return here to get started
2. Use the integrated terminal to navigate to the import-warmup/ directory if you're not already there
3. Verify that your Codespace is set up correctly by running python3.14 --version. The output should be Python 3.14.0.

Exercise 1: Basic Imports

This exercise introduces the types of errors you'll see when your imports are missing or incorrect, as well as providing practice on fixing them.

Task 1.1: Correct Initial import Errors

Run the run_exercises.py file:

python3.14 run_exercises.py

You'll see the following NameError:

File "/workspaces/import-warmup/run_exercises.py", line 1, in <module>
    my_portfolio = portfolio.data.create_portfolio("Retirement")
                   ^^^^^^^^^
NameError: name 'portfolio' is not defined

Add import statement(s) to the run_exercises.py file so that the above NameError is resolved. Do not change any other code in the file.

Success

If you've succeeded, the NameError: name 'portfolio' is not defined error is replaced with a new error: NameError: name 'make_asset' is not defined

Reflection

1. What's the difference between a NameError and an ImportError in the context of imports?
2. Why does Python require explicit import statements rather than automatically finding all available code?

Task 1.2: Correct NameError

The error message tells you that make_asset is not defined. Find where make_asset is defined and add the necessary import statement(s) to the file(s) that use it. Do not modify any of the existing code.

Success

You'll know you succeeded when the above NameError is replaced with the following error:

Traceback (most recent call last):
  File "/workspaces/import-warmup/run_exercises.py", line 4, in <module>
    portfolio.report.print_report(my_portfolio)
    ^^^^^^^^^^^^^^^^
AttributeError: module 'portfolio' has no attribute 'report'

Note: You may have thought ahead during Task 1.1, above, and may have already corrected the problem that causes the AttributeError above. If you don't see the above AttributeError, get no other errors and your report prints to the screen, follow the link at the end of this document to go to Part 2 of the lab.

Task 1.3: Correct further errors revealed in run_exercises.py

Add import statement(s) to run_exercises.py so that the above AttributeError is resolved. Do not modify any of the existing code.

Success

You'll know you succeeded when running python3.14 run_exercises.py results in no errors and you have a report printed to the screen.

Task 1.3: Commit and Push your Changes

Run git status on your repo to see the changes you made. You'll notice that there are several __pycache__ folders in your codebase. These are auto-generated when you import modules into your code and contain bytecode for the modules you import in your project as a way of speeding up subsequent imports. They can be safely deleted since they'll be regenerated when needed, so they should not be committed to your repo.

Create a .gitignore file in your repo and add __pycache__ to it. Add, commit, and push your changes to your repo.

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Next up: Exercise 2: Imports and Refactored Code