Dynamic users' home directories are set to '/'

Here are the details of the dynamic user created.
```
(base) [root@jupyter jupyterenv]# getent passwd jupyter-someuser-singleuser
jupyter-someuser-singleuser:*:65492:65492:Dynamic User:/:/sbin/nologin
(base) [root@jupyter jupyterenv]#
```
And here is one of the issues it causes.
```
[jupyter-someuser-singleuser@jupyter ~]$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (//.ssh/id_rsa):
Could not create directory '//.ssh': Read-only file system
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Saving key "//.ssh/id_rsa" failed: No such file or directory
[jupyter-someuser-singleuser@jupyter ~]$

```

Here are the relevant variables.
```
USER=jupyter-someuser-singleuser
PWD=/var/lib/someuser
HOME=/var/lib/someuser
MAIL=/var/spool/mail/jupyter-someuser-singleuser
LOGNAME=jupyter-someuser-singleuser
```

How do I configure **systemdspawner** to set users to the correct home directory?