Not defined inter-state lines in Japan? Any other countries?

Hi,

I'm making a map with Basemap of Japan.
However, I could not draw the inter-state borders in Japan.
My snippet is like below.

# setting the two corners of the map 
lon0, lat0 = (125, 25)
lon1, lat1 = (150, 46)
# creating a Basemap object
m = Basemap(projection='merc',llcrnrlon=lon0, llcrnrlat=lat0,
            urcrnrlon=lon1, urcrnrlat=lat1,  resolution='l')
x0, y0 = m(lon0, lat0)
x1, y1 = m(lon1, lat0)
plt.figure(figsize=(15,10))
# drawing coastlines, effective
m.drawcoastlines()
# fill out continent area with a specified color
m.fillcontinents(color='coral',lake_color='aqua')
# fill out ocean area with a specified color
m.drawmapboundary(fill_color='aqua')
# drawing country-border lines, effective
m.drawcountries()
# drawing inter-state lines, not effective
m.drawstates()

Therefore, drawstates method is not working well for Japan.
Please let me ask several questions on this matter.

Q. Is there not defined the inter-state lines in Japan with Basemap?

Q. If not, how should we add codes and data to the Basemap repository?

Q. Is there any other countries where their inter-state lines have not defined yet?

Thanks for your kind answers.

Best,
Takeshi

Start by reproducing the provided Basemap snippet and examining the drawstates method and its boundary data for Japan. Determine whether the missing inter-state lines are unsupported or absent data, then document the finding or identify the repository data and code that would need updating.