def make_data_column_long(data_in, var_name):
    """
    
    Takes a specfic variable from the raw oTree data
    and takes the subset of this data for each participant
    round and super game.
    """
    data_out = data_in.loc[data_in['variable'] == var_name][['participant.code', 'round', 'super_game', 'value']].copy()
    data_out.rename({'value': var_name}, inplace=True, axis=1)
    return data_out