Retrieving battery electrodes data using the new API

Hello everyone,
I have tried to retrieve electrodes data with different working ions. I keep getting errors, please anyone to assist me over come this error.
This is the code i used

from mp_api import MPRester
battery_list2 = pd.DataFrame()
with MPRester(“11111111111111111111111”) as mpr:
battery_list = mpr.insertion_electrodes.search_electrode_docs(“Li”, all_fields=True)
battery_list2 = battery_list2.append(battery_list, ignore_index=True)