Overwrite a PDF item type with ArcGIS API for Python

I’m trying to overwrite an existing PDF ArcGIS Online item using ArcGIS API for Python.

props = {
    "type":"PDF",
    "title":file_name,
    "overwrite":True
    }

data = os.path.join(tempFolder, "{}.pdf".format(file_name))

gis.content.add(item_properties=props, data=data)

Returns

RuntimeError: Item already exists

props = {
    "type":"PDF",
    "title":file_name,
    "overwrite":True
    }

data = os.path.join(tempFolder, "{}.pdf".format(file_name))

item = gis.content.get('itemuniqueid')
item.update(item_properties=props, data=data)