def is_grease(int_value):
    """
    Returns if a value is GREASE.

    See https://tools.ietf.org/html/draft-ietf-tls-grease-01

    """
    hex_str = hex(int_value)[2:].lower()
    if len(hex_str) < 4:
        return False

    first_byte = hex_str[0:2]
    last_byte = hex_str[-2:]

    return (
        first_byte[1] == 'a' and
        last_byte[1] == 'a' and
        first_byte == last_byte
    )