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

        url = self._tuple
        if url.username and url.password:
            netloc = '%s:%s@%s' % (url.username, url.password, url.host)
        elif url.username and not url.password:
            netloc = '%s@%s' % (url.username, url.host)
        else:
            netloc = url.host
        if url.port:
            netloc = '%s:%s' % (netloc, url.port)
        return netloc