IAM CLI issues

When trying to extend the guest account I get the following error.

iam guest extend rtestaccount
Error: len() takes exactly one argument (2 given)

Version

iam --version
IAM command line tool, version 0.15.2

User details

iam person rtestaccount
{
    "category": null,
    "description": "Authorized Leonhard Med guest",
    "firstname": "RPOPS",
    "gidNumber": "504616",
    "lastname": "Testaccount",
    "mail": "shock@foolishcleverness.org",
    "npid": "4067472",
    "nuid": null,
    "orcid": null,
    "persid": null,
    "perskats": [],
    "title": null,
    "uidNumber": "627251",
    "username": "rtestaccount",
    "usernames": []
}

Creating a new guest seems to also have issues. However, the account was created (see below).

iam guest new -f Thavayogarajah -l Thavayogarajah -m tharshika.thavayogarajah@usz.ch -d "Authorized Leonhard Med guest" -h bcasano -a "ID SIS" -n t -c leomed-support@id.ethz.ch
Traceback (most recent call last):
  File "/home/bmx/venvs/leomed/bin/iam", line 8, in <module>
    sys.exit(cli())
  File "/home/bmx/venvs/leomed/lib/python3.10/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
  File "/home/bmx/venvs/leomed/lib/python3.10/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
  File "/home/bmx/venvs/leomed/lib/python3.10/site-packages/click/core.py", line 1688, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/bmx/venvs/leomed/lib/python3.10/site-packages/click/core.py", line 1688, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/bmx/venvs/leomed/lib/python3.10/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/bmx/venvs/leomed/lib/python3.10/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
  File "/home/bmx/venvs/leomed/lib/python3.10/site-packages/click/decorators.py", line 92, in new_func
    return ctx.invoke(f, obj, *args, **kwargs)
  File "/home/bmx/venvs/leomed/lib/python3.10/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
  File "/home/bmx/venvs/leomed/lib/python3.10/site-packages/ethz_iam_webservice/main.py", line 742, in new_guest
    guest = iam.new_guest(
  File "/home/bmx/venvs/leomed/lib/python3.10/site-packages/ethz_iam_webservice/person.py", line 546, in create
    guest = self.new_from_data(data)
  File "/home/bmx/venvs/leomed/lib/python3.10/site-packages/ethz_iam_webservice/person.py", line 350, in new_from_data
    new_guest["mail"] = new_guest["mail"][0] if len(new_guest.get("mail"),[]) else None
TypeError: len() takes exactly one argument (2 given)****

Account details

iam user tthavayogara
{
    "cre_by": "DomainAdmin",
    "cre_date": "23-DEC-2024",
    "description": "Authorized Leonhard Med guest",
    "gidNumber": null,
    "givenName": null,
    "home_directory": null,
    "login_shell": null,
    "mod_by": "DomainAdmin",
    "mod_date": "23-DEC-2024",
    "npid": "4078507",
    "nuid": "6154531",
    "services": [
        {
            "Assigned by": "",
            "delete_after": "2025-12-23",
            "enabled": "1",
            "login_until": "2025-12-23",
            "name": "LDAP"
        },
        {
            "Assigned by": "",
            "delete_after": "2025-12-23",
            "enabled": "1",
            "login_until": "2025-12-23",
            "name": "WLAN_VPN"
        }
    ],
    "sn": "Thavayogarajah",
    "uidNumber": null,
    "username": "tthavayogara",
    "valid_until": "23-DEC-2025"
}