<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def my_address_string(self):
 """ For logging client host without resolving. """

        addr = getattr(self, 'client_address', ('', None))[0]

        # If listed in proxy_ips, use the X-Forwarded-For header, if present.
        if addr in self.proxy_ips:
            return self.headers.getheader('x-forwarded-for', addr)
        return addr