US Open ที่มี Maikel Scheffers เป็นพันธมิตรในปีใด
What year was the US Open that had a partnering of Maikel Scheffers?
df = pd.DataFrame(columns=['year', 'partnering', 'championship'])
df.loc[(df['partnering'] == 'Maikel Scheffers') & (df['championship'] == 'US Open'), 'year'].sum()