Currently column configuration in storage backends cannot be used in executors because List[Tuple[str, str]] is not a json or Yaml parsable type
Probably we need to switch to a better format like

[
    {
        "name": "col1",
        "type": "str"
    },
]

or [["col1", "str"],]
or

{
    "col1": "str",
    "col2": "int",
}