def escape_b(s, quote=True):
    '''Replace special characters "&", "<" and ">" to HTML-safe sequences.
    If the optional flag quote is true, the quotation mark character (")
    is also translated.'''
    s = s.replace(b"&", b"&amp;") # Must be done first!
    s = s.replace(b"<", b"&lt;")
    s = s.replace(b">", b"&gt;")
    if quote:
        s = s.replace(b'"', b"&quot;")
    return s
Replace special characters "&", "<" and ">" to HTML-safe sequences.
    If the optional flag quote is true, the quotation mark character (")
    is also translated.