gistfile1.py

class Day(Enum):
    MONDAY = 0
    TUESDAY = 1
    WEDNESDAY = 2
    THURSDAY = 3
    FRIDAY = 4
    SATURDAY = 5
    SUNDAY = 6

def encode(days: set) -> int:
    result = 0
    for day in days:
        result |= 1 << day.value
    return result

def decode(bits: int) -> set:
    return {Day(i) for i in range(7) if bits & 1 << i}