1. Design a function contract
TASK: Write a line_value function and predict outputs for (2,1000), (1,0), (0,1000), (-1,500) and (True,100).
Your method:
Your evidence/result:
Limitations and next action:


2. Read files with explicit context and encoding
TASK: Read order_lines.csv through DictReader and compute its SHA-256. Import your module from a second script and confirm that its command-line path does not run automatically.
Your method:
Your evidence/result:
Limitations and next action:


3. Handle expected errors without hiding defects
TASK: Run the supplied validation cases and add a missing-file test. Classify each as an invalid input, fatal source problem or programmer defect.
Your method:
Your evidence/result:
Limitations and next action: