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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def sanitize_jid(s):
 """Generates a valid JID node identifier from a string"""

    jid = unicode_to_ascii(s).lower()
    jid = WHITESPACE.sub('-', jid)
    jid = INVALID_JID_CHARS.sub('', jid)
    return jid.strip()[:256]