Could you please help me sort out the below if condition:
(could be also possible with apply and lambda but don’t know how to put so many conditions in single line)

test = pd.DataFrame({'index' : ['DS','VS','VB','FS','HB'],
   'bid' : [np.nan,102,103,104,np.NaN],
   'mid'  : [106,107,108,109,110],
    'ask' : [np.nan,112,113,114,115]})

print(test)

  index    bid  mid    ask
0    DS    NaN  106    NaN
1    VS  102.0  107  112.0
2    VB  103.0  108  113.0
3    FS  104.0  109  114.0
4    HB    NaN  110  115.0

What I tried :

if (test['index'].str.endswith('B') and test['bid'] > 0).all():
    test['fin'] == test['bid']
elif (test['index'].str.endswith('S')) and (test['ask'] > 0).all():
    test['fin'] == test['ask']
elif test['bid'] > 0:
    test['fin'] == test['bid']
elif test['mid'] > 0:
    test['fin'] == test['mid']
else:
    test['fin'] == test['ask']

Still getting the error message:

ValueError: The truth value of a Series is ambiguous. Use a.empty,
a.bool(), a.item(), a.any() or a.all()

.