Remove empty keys in a python list

[python_student]

I have a list of dictionaries and in case if some dictionary has empty key I want to remove it completely from the list. In my example,
I need to remove all third block because column3 is empty.

a = [
    {
        "type": "some.type2",
        "payload": {
            "column1": "12345",
            "column2": "description",
            "column3": 98
        }
    },
    {
        "type": "some.type2",
        "payload": {
            "column1": "12345",
            "column2": "description",
            "column3": 180
        }
    },
    {
        "type": "some.type2",
        "payload": {
            "column1": "12345",
            "column2": "description",
            "column3": ""
        }
    }    
]

This is my code but is not removing and I think it's because of json structure

a = [d for d in payload if "" not in d.values()]

print(type(a))
<class 'list'>

Does anyone knows how can I solve it?