from typing import Dict


def correct_artigau_2018(band: str) -> float:
    """Apply Artigau et al. (2018) Table 3 nominal Barnard's Star corrections.

    Parameters
    ----------
    band: str
       Wavelength band.

    Returns
    -------
    correction: float
       Correction value to multiply synthetic model precisions by to get to "real" values.

    Warning
    -------
    Returns the corrections from the nominal (second) column only.

    """

    corrections: Dict[str, float] = {
        "g": 0.66,
        "r": 0.82,
        "i": 0.94,
        "Z": 1.27,
        "z": 1.27,
        "Y": 0.29,
        "J": 0.38,
        "H": 1.37,
        "K": 1.47,
    }
    try:
        return corrections[band]
    except KeyError:
        raise KeyError("Band '{}' does not have a valid correction key".format(band))