import re


def is_date_range(start, end):
    """Checks for YYYY-MM-DD date format."""
    return bool(
        re.match("^2[0-9]{3}-[0-9]{2}-[0-9]{2}$", start)
        and re.match("^2[0-9]{3}-[0-9]{2}-[0-9]{2}$", end)
    )