The Base class

base_class.py

class Base(object):
    def __repr__(self):
        try:
            u = self.__str__()
        except (UnicodeEncodeError, UnicodeDecodeError):
            u = '[Bad Unicode data]'
        repr_type = type(u)
        return repr_type('<%s: %s>' % (self.__class__.__name__, u))

    def __str__(self):
        if hasattr(self, '__unicode__'):
            if PY3:
                return self.__unicode__()
            else:
                return unicode(self).encode('utf-8')
        return txt_type('%s object' % self.__class__.__name__)