class BinaryData(object):
    '''The minimal example'''

    def __init__(self, data):
        if not data:
            raise TypeError("no data to parse")
        if len(data) <= 1:
            raise ValueError("data too short")

        self.data = data
        self.length = len(data)

    def __repr__(self):
        # The debugger runs this before __init__ is even done, so it will
        #   complain about BinaryData not having an attribute length
        return "<%s: length %d>" % (self.__class__.__name__, self.length)
        
        # If you replace the above with this (or remove __repr__ entirely),
        #   it works fine
        # return "A constant string"