How do i use inequality signs for conditions in dictionaries or tupples

I have a Python dict consisting of units and scores:

Unit_scores = {"micro":63, "macro":72, "stat":56}

I want to create grading conditions so that:

• A is a score between 70 and 80,
• B between 60 and 70 and
• C between 50 and 60

How do I go about that?