import string
import random


def random_string(choose_from=None, length=8):
    """
    Return a random sequence of characters

    Args:
        choose_from (Sequence): he set of eligible characters - by default
            the set is string.ascii_lowercase + string.digits
        length (int): the length of the sequence to be
            returned (in characters, default 8)
    Returns (string)
    """
    choices = list(choose_from or (string.ascii_lowercase + string.digits))
    return "".join(random.choice(choices) for _ in range(length))