import re


def norwegian_ascii(unicode_str):
    """
    Return an ASCII string with Norwegian chars replaced with their closest
    ASCII representation. Other non-ASCII characters are ignored and removed.
    """
    unicode_str = re.sub(r"ø", "oe", unicode_str, flags=re.IGNORECASE)
    unicode_str = re.sub(r"æ", "ae", unicode_str, flags=re.IGNORECASE)
    unicode_str = re.sub(r"å", "aa", unicode_str, flags=re.IGNORECASE)
    return unicode_str.encode("ascii", "ignore").decode()