def gatherAttrs(self):
		attrs = []
		for key in sorted(self.__dict__):
			attrs.append('%s=%s)'%(key,getattr(self,key)))
		return ','.join(attrs)

>>> a='231231'
>>> b=[123,'zxc',True]
>>> b
[123, 'zxc', True]
>>> a.join(b)
Traceback (most recent call last):
  File "<pyshell#19>", line 1, in <module>
    a.join(b)
TypeError: sequence item 0: expected str instance, int found