set default to "" while extracting basis

def extract_basis_table(dlist: list[dict], basis_keys: tuple) -> table.Table:

    """Extract basis key-value pairs from a list of dictionaries."""

    return table.Table([{k: d.get(k) for k in basis_keys} for d in dlist])

    return table.Table([{k: d.get(k, default="") for k in basis_keys} for d in dlist])

def split_data_basis(data_basis: table.Table, n_split: int = 1) -> list[table.Table]:

        plan_basis: table.Table,

        data_basis: table.Table,

        # n_jobs: int = 1,

    ):

    ) -> list[dict]:

        # return an empty list if input is empty

        if len(plan_basis) == 0 or len(data_basis) == 0:

            return []