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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 salt_token_tool():
    '''
    If the custom authentication header is supplied, put it in the cookie dict
    so the rest of the session-based auth works as intended
    '''
    x_auth = cherrypy.request.headers.get('X-Auth-Token', None)

    # X-Auth-Token header trumps session cookie
    if x_auth:
        cherrypy.request.cookie['session_id'] = x_auth