exit()
#Setup login credentials and input file location
username = str(sys.argv[1])
pw = str(sys.argv[2])
input_file_loc = dir_input + str(sys.argv[3])
#Ensure that the input file location exists
if ( not os.path.isfile(str(input_file_loc)) ):
print "The file " + str(input_file_loc) + " does not exist."
exit()
#login credentials to datastream
DWE = Datastream(username=username,password=pw)
#other info from datastream
info = DWE.system_info()
subscribed_sources = DWE.sources()
#replace missing data with NaNs
DWE.raise_on_error = False
#get all codes, groups, start dates from input file
with open(input_file_loc,'r') as input_file:
symbol_ref = json.load(input_file)
#download timestamp
download_date = {'Custom_Download_Date' : datetime.datetime.now().isoformat()}
#calculate time taken for entire process
time_taken = datetime.datetime.now()
time_taken = time_taken - time_taken
