How to fix invalida polygons in shapely

test.py

from shapely.geometry import Polygon, MultiPolygon
from shapely.ops import polygonize
import numpy as np
from skimage import draw, io

img = np.zeros(shape=(600, 600, 3), dtype=np.uint8)

coords = np.array([[20, 20], [20, 400], [400, 20], [400, 400]], dtype=np.int32)

p = Polygon(coords)
rr, cc = draw.polygon_perimeter(np.int32(p.exterior.coords[:])[:, 0],
                                np.int32(p.exterior.coords[:])[:, 1])
img[rr, cc] = [255, 0, 255]
io.imshow(img)
io.show()

print(f"{type(p)} {p.is_valid}")
print(f"{type(p)} {p.is_empty}")
print(f"{type(p)} {p.is_closed}")
print(f"{type(p)} {p.is_simple}")
print(f"{type(p)} {p.area}")
print()

p = p.exterior
p = p.intersection(p)
p = polygonize(p)
p = MultiPolygon(p)
print(f"{type(p)} {p.is_valid}")
print(f"{type(p)} {p.is_empty}")
print(f"{type(p)} {p.is_closed}")
print(f"{type(p)} {p.is_simple}")
print(f"{type(p)} {p.area}")
print()

for p in p:
    img[:] = 0
    rr, cc = draw.polygon_perimeter(np.int32(p.exterior.coords[:])[:, 0], np.int32(p.exterior.coords[:])[:, 1])
    img[rr, cc] = [255, 0, 255]
    io.imshow(img)
    io.show()
    print(f"{type(p)} {p.is_valid}")
    print(f"{type(p)} {p.is_empty}")
    print(f"{type(p)} {p.is_closed}")
    print(f"{type(p)} {p.is_simple}")
    print(f"{type(p)} {p.area}")
    print()