from typing import List
from typing import Tuple


def column_labels_level(column_labels: List[Tuple]) -> int:
    """Return the level of the column index."""
    if len(column_labels) == 0:
        return 1
    else:
        levels = set(1 if label is None else len(label) for label in column_labels)
        assert len(levels) == 1, levels
        return list(levels)[0]