Loading Json File - Need help

[lejencodes]

An iterable of params

@parameterized(
param.explicit(*json.loads(line))
for line in open("testcases.jsons")
)
def test_from_json_file(...):
...

Trying to follow the guide of loading json file, is there any particular format of json that we need to follow here?
I am getting TypeError: type object argument after ** must be a mapping, not str

Sample json:
{"birthday": "1956-01-31T12: 00: 00Z", "name": "Guido van Rossum"}