'Parser constructor
@param stream: Data input stream (see L{InputStream})
@param description: (optional) String description'

def __init__(self, stream, description=None):

    assert (hasattr(self, 'endian') and (self.endian in (BIG_ENDIAN, LITTLE_ENDIAN, MIDDLE_ENDIAN)))
    GenericFieldSet.__init__(self, None, 'root', stream, description, stream.askSize(self))
