def METHOD_NAME(params, transforms, profiles, data, **kwargs):
    # Implements equation 4.20 in M. Landreman & R. Jorge (2020)
    # doi:10.1017/S002237782000121X.
    data["D_Mercier"] = (
        data["D_shear"] + data["D_current"] + data["D_well"] + data["D_geodesic"]
    )
    # The axis limit does not exist as D_Mercier is of the order ρ⁻² near axis.
    return data