AttributeError: 'dict' object has no attribute 'version_type' when trying to use git_client.get_commits search_criteria

When trying to get all the commits on a branch I get an attribute error.

Code:
from azure.devops.connection import Connection
from azure.devops.v7_0.git import GitClient
from azure.devops.v7_0.git.models import GitQueryCommitsCriteria
from msrest.authentication import BasicAuthentication

cm_search_criteria = GitQueryCommitsCriteria(
item_version={"version": branch_name,"versionType": 'branch'}
)

        print (f"search critera")
        print (cm_search_criteria)
        print (f"search critera")
        
        commits = git_client.get_commits(
            repo_name,
            project=project_name,
            search_criteria=cm_search_criteria
        )    

Results:
Traceback (most recent call last):
File "C:\PythonWork\Tool Connectivity\ADO_ALL_REPOS_BRANCHES_COMMITS.py", line 66, in
commits = git_client.get_commits(
repo_name,
project=project_name,
search_criteria=cm_search_criteria
)
File "C:\Users\tmoran\AppData\Local\Programs\Python\Python313\Lib\site-packages\azure\devops\v7_0\git\git_client_base.py", line 361, in get_commits
if search_criteria.item_version.version_type is not None:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'dict' object has no attribute 'version_type'

I cannot see anything wrong with the code, but it is throwing an error, does any one see an error?

Beginne mit azure/devops/v7_0/git/git_client_base.py etwa ab Zeile 361 und dem GitQueryCommitsCriteria-Modell, das von get_commits verwendet wird. Vergleiche die erwartete Form des item_version-Modells mit dem im Beispiel bereitgestellten Dictionary. Die Aufgabe ist abgeschlossen, wenn die Branch-Kriterien ohne den AttributeError an get_commits übergeben werden können und die Commit-Abfrage abgeschlossen wird.