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

def SetAuth(self, style, user=None, password=None):
        '''Change auth style, return object to user.
        '''
        self.auth_style, self.auth_user, self.auth_pass = \
            style, user, password
        return self