import time
import eikon as ek
ek.set_app_key('In here with your app key...')
static_flds = ['TR.IndexConstituentRIC', 'TR.IndexConstituentName']
for x in range(100):
    print('round: ', x)
    err_const = 0 # random stuff
    err_isin = 0 # random stuff again
    while err_const is not None:
        try:
            inst_list, err_const = ek.get_data(instruments=['.STOXX'], fields=static_flds,
                                               parameters={'SDate': '2017-01-15',
                                                           'EDate': '2017-01-15'})
        except:
            pass

    while err_isin is not None:
        try:
            isin_list, err_isin = ek.get_data(instruments=inst_list.loc[:, 'Constituent RIC'].tolist(),
                                              fields=['TR.ISINCode', 'TR.SEDOL'])
        except:
            pass
    if (isin_list['ISIN Code'].values == '').sum() > 0:
        print(isin_list.head(5))
        print('Weird stuff going on in this loop!')
    print()
    time.sleep(2)
print('end')