index_total_returns fails with JSONDecodeError

[vikaskojha]

Calling index_total_returns throws a JSONDecodeError. The endpoint https://niftyindices.com/Backpage.aspx/getTotalReturnIndexString seems to return non‑JSON (possibly empty or HTML).

Steps to Reproduce:

from nsepython import index_total_returns
symbol = "NIFTY 50"
start_date = "06-Jul-2026"
end_date = "06-Jul-2026"
print(index_total_returns(symbol,start_date,end_date))

Error:
requests.exceptions.JSONDecodeError: Expecting value: line 1 column 2 (char 1)

Environment:
Windows 11
Python 3.13
nsepython 2.97

Expected:
Function should print total return index values.

Actual:
Fails with JSONDecodeError.