Polymorphism in Real-World Code | Dataford Interview Questions

Write a program to demonstrate polymorphism in a real-world scenario.

Implement process_documents(documents) using a shared document interface and separate subclasses for invoices, forms, and contracts. Each subclass must override the same processing method, and the main function must process all inputs polymorphically without type-specific calculation logic in its iteration loop.

Input is a list of dictionaries. Each dictionary contains kind and fields required by that kind. Return an object containing per-document results and the total cost.

Supported calculations: invoices cost pages * 2 plus 5 for urgent priority, forms cost pages + attachments * 2, and contracts cost pages * 3 + clauses.

Constraints

0 <= len(documents) <= 10000
Each document kind is one of: invoice, form, contract
Invoice pages and form pages are nonnegative integers
Invoice priority is either normal or urgent
Form attachments and contract clauses are nonnegative integers

Function Signature

def process_documents(documents):

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