import re


def is_acquired(acquired):
    """Is the date string a / separated date range in iso8601 format?

    Args:
        acquired: A date string

    Returns:
        bool: True or False
    """

    # 1980-01-01/2015-12-31
    regex = '^[0-9]{4}-[0-9]{2}-[0-9]{2}\/[0-9]{4}-[0-9]{2}-[0-9]{2}$'
    return bool(re.match(regex, acquired))