buildwithmh

class StringBuilder(object):
    def __init__(self, val):
        self.store = [val]

    def __iadd__(self, value):
        self.store.append(value)
        return self

    def __str__(self):
        return "".join(self.store)

buildwithmh

def is_prime(*, number: int):
    stop = int(math.sqrt(number)) + 1
    return all(number % divisor != 0 for divisor in range(2, stop))