Registers a new generator class, specifying a set of
        properties relevant to this scanner.  Ctor for that class
        should have one parameter: list of properties.

def register(scanner_class, relevant_properties):
    """ Registers a new generator class, specifying a set of
        properties relevant to this scanner.  Ctor for that class
        should have one parameter: list of properties.
    """
    assert issubclass(scanner_class, Scanner)
    assert isinstance(relevant_properties, basestring)
    __scanners[str(scanner_class)] = relevant_properties