def map_label(row, label_map):
    """
    Creating a touple using two pre-existing columns, then using this touple as the key to look up table label in the dictionary
    
    Parameters
    ----------
        row: row
            this function will apply to every row in the dataframe
        label_map: dictionary
            where the label will be identified
    
    Returns
    --------
    table_label:str
        the label to be applied to that variable in the output table
    
    """
    key  = (row["variable_name"], row["value_label"])
    table_label = label_map[key]
    return table_label