<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def as_list(self):

 """
 returns a list version of the object, based on it's attributes
 """

        if hasattr(self, 'cust_list'):
            return self.cust_list
        if hasattr(self, 'attr_check'):
            self.attr_check()
        cls_bltns = set(dir(self.__class__))
        ret = [a for a in dir(self) if a not in cls_bltns and getattr(self, a)]
        return ret