Attempt to use 'pymatgen.analysis.defects.core', 'Defect'

Hi, as mentioned in the subject, I am trying to use ‘pymatgen.analysis.defects.core’, but somehow it keeps giving me an error.

In my jupyternotebook, I used ‘pymatgen.core.sites’ as well, and it seems like there wasn’t an error at this part.

I’m assuming that it would be a problem with giving the parameters in a wrong form, but could find where I made the mistake.

from pymatgen.core import Structure
CsCu2I3 = Structure.from_file("CONTCAR_perfect")
CsCu2I3_V_Cs1_1m1 = Structure.from_file("CONTCAR_V_Cs1_1m1")

from pymatgen.core.sites import Site as st
import numpy as np
coords = [0.3310489327811865, 0.6689510672199646, 0.8750000000000000]
site = st("Cs", coords)

from pymatgen.analysis.defects.core import Defect as df
defect = df(structure = CsCu2I3, defect_site = site, charge = -1.0)

below is the captured screen of my jupyer notebook.