bite_207.py

# Online Python - IDE, Editor, Compiler, Interpreter
import random
from functools import wraps
from time import sleep


def cached_property(func):
    """decorator used to cache expensive object attribute lookup"""

    @wraps(func)
    def getter(self, *args, **kwargs):
        if not hasattr(cached_property, "cache"):
            cached_property.cache = dict()
        if func not in cached_property.cache:
            cached_property.cache[func] = func(self)
        return cached_property.cache[func]

    return getter


class Planet:
    """the nicest little orb this side of Orion's Belt"""

    GRAVITY_CONSTANT = 42
    TEMPORAL_SHIFT = 0.12345
    SOLAR_MASS_UNITS = 'M\N{SUN}'

    def __init__(self, color, _mass =None):
        self.color = color
        self._mass = None

    def __repr__(self):
        return f'{self.__class__.__name__}({repr(self.color)})'

    @cached_property
    def mass(self):
        scale_factor = random.random()
        sleep(self.TEMPORAL_SHIFT)
        self._mass = (f'{round(scale_factor * self.GRAVITY_CONSTANT, 4)} '
                      f'{self.SOLAR_MASS_UNITS}')
        return self._mass
        
    mass = property(mass)

planet = Planet('Blue', 17.15)
#print(planet)
masses = [planet.mass for _ in range(10)]
print(masses)