class AttrDisplay:
  def gatherAttrs(self):
    return ",".join("{}={}"
            .format(k, getattr(self, k))
            for k in self.__dict__.keys())
    # attrs = []
    # for k in self.__dict__.keys():
    #   item = "{}={}".format(k, getattr(self, k))
    #   attrs.append(item)
    # return attrs
    # for k in self.__dict__.keys():
    #   attrs.append(str(k) + "=" + str(self.__dict__[k]))
    # return ",".join(attrs) if len(attrs) else 'no attr'

  def __str__(self):
    return "[{}:{}]".format(self.__class__.__name__, self.gatherAttrs())

class Bean(AttrDisplay):
  def __init__(self, id=1024, name='Jack Chen', job='Actor'):
    self.id = id
    self.name = name
    self.job = job

  def doSomething(self):
    return self.name + " doing something now ..."


if __name__ == '__main__':
  bob = Bean()
  print(bob)
# [Bean:id=1024,name=Jack Chen,job=Actor]