def df_last_column(df, column_name):
    """Move a dataframe column to the right-most position.
    
    Parameters
    ----------
    df: :class:`pandas.DataFrame`
        Dataframe to rearrange
        
    column_name: :obj:`str`
        Column to move.
    Returns
    ----------
    :class:`pandas.DataFrame`
        Rearranged dataframe
    """
    cols = list(df)
    cols.insert(len(cols), cols.pop(cols.index(column_name)))
    return df.loc[:, cols]