from typing import Iterable
from typing import List


def make_error_col_names(qcols: Iterable) -> List:
    """helper func to make error column names of the form
    <col_name>_low ... <col_name>_high
    Args:
        qcols (iterable): an iterable of column names used for matching
    Returns:
        list: list of error col names in non-interleaved order
    """
    error_cols = [f"{dcol}_low" for dcol in qcols]
    error_cols = error_cols + [f"{dcol}_high" for dcol in qcols]
    return error_cols