Load the counter object file using the GXDLMSObjectCollection.load method for gurux dlms python

Hello, please help me,

When I try to load my collectionObject file using the method, GXDLMSObjectCollection.load from the gurux library for python, I get the error: can only concatenate str (not "GXDLMSData") to str.

The file is saved in .xml format and the structure seems correct. Below is an extract from my code:

reader.initializeConnection()
path = Path(os.getcwd())
path = path.joinpath("devices.xml")
print(path.absolute())
try:
t = GXDLMSObjectCollection.load(file_=path.absolute())
except Exception as ex:
print(ex)

Thanks in advance for your help