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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def _key_opts(self):
        '''
        Return options for the ssh command base for Salt to call
        '''
        options = [
                   'KbdInteractiveAuthentication=no',
                   ]
        if self.passwd:
            options.append('PasswordAuthentication=yes')
        else:
            options.append('PasswordAuthentication=no')
        if self.opts.get('_ssh_version', (0,)) > (4, 9):
            options.append('GSSAPIAuthentication=no')
        options.append('ConnectTimeout={0}'.format(self.timeout))
        if self.opts.get('ignore_host_keys'):
            options.append('StrictHostKeyChecking=no')
        if self.opts.get('no_host_keys'):
            options.extend(['StrictHostKeyChecking=no',
                            'UserKnownHostsFile=/dev/null'])
        known_hosts = self.opts.get('known_hosts_file')
        if known_hosts and os.path.isfile(known_hosts):
            options.append('UserKnownHostsFile={0}'.format(known_hosts))
        if self.port:
            options.append('Port={0}'.format(self.port))
        if self.priv and self.priv != 'agent-forwarding':
            options.append('IdentityFile={0}'.format(self.priv))
        if self.user:
            options.append('User={0}'.format(self.user))
        if self.identities_only:
            options.append('IdentitiesOnly=yes')

        ret = []
        for option in options:
            ret.append('-o {0} '.format(option))
        return ''.join(ret)