Code Clean-Up

[stephaniexiao]

Description of changes:

• Standardized variable styles "itemId" -> "item_id"
• Moved import statement to top
• Added static variable to account for purchases above 250 for 17 reward points
• Added an error log array to replace the raised ValueError
• Simplified process log method: only general cases (for both customers with and without ids) and reward points cases
• Removed unnecessary get_items_purchased method
• Removed unnecessary comments
• Removed unnecessary print statements

Which files were touched:

• rewardPointsSystem.py

Notes for PMs:

• Left a few comments in the code--not sure if they should be considered necessary or unnecessary

Relevant Issue: #1
Fixes #8

[kelvinjue]

Good work here! We'll be going over these during one of our meetings this week.