<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def pick_summary_data(key, summary_df, selected_summaries):
 """picks the selected pandas.DataFrame"""


    selected_summaries_dict = create_selected_summaries_dict(selected_summaries)
    value = selected_summaries_dict[key]
    return summary_df.iloc[:, summary_df.columns.get_level_values(1) == value]