Map data element numbers to pvlib names.

    Parameters
    ----------
    col: str
        Column label to be mapped.

    Returns
    -------
    str
        The pvlib label if it was found in the mapping,
        else the original label.

def map_columns(col):
    """Map data element numbers to pvlib names.

    Parameters
    ----------
    col: str
        Column label to be mapped.

    Returns
    -------
    str
        The pvlib label if it was found in the mapping,
        else the original label.
    """
    if col.startswith('7'):
        # spectral data
        try:
            return VARIABLE_MAP[col]
        except KeyError:
            return col
    try:
        variable_name = VARIABLE_MAP[col[:3]]
        variable_number = col[3:]
        return variable_name + '_' + variable_number
    except KeyError:
        return col