Code

import pandas as pd

logs = pd.read_csv('/datasets/logs.csv')
logs['email'] = logs['email'].fillna(value='')
logs.loc[logs['source'] == 'None', 'source'] = 'email'

logs_grouped = logs.groupby('source')['purchase'].agg(['count', 'sum'])#запишите ваш код сюда

print(logs_grouped)