I am using the Datastream API for Python. It returns "NA" values - when I use the "DSGRID" Excel Add-in on the same list of securities, I get the required "SECD" values. My code:
securities = ['US0235861004', 'US29362U1043', 'US5393192027', 'US07134L1070', 'CA91702V1013', 'US0008681092', 'US4281031058', 'US16411R2085', 'INE733E01010', 'US18270D1063']
fields = ['SECD']
sec_str = "".join(['{},'.format(x) for x in securities])[:-1]
secd_list = ds.get_data(tickers=sec_str, fields=fields, kind=0)
Output: