#===============register.py====================##
#!/usr/bin/env python
# -*- coding:utf-8 -*-
import sys
from _winreg import *
 
# tweak as necessary
version = sys.version[:3]
installpath = sys.prefix
 
regpath = "SOFTWARE\\Python\\Pythoncore\\%s\\" % (version)
installkey = "InstallPath"
pythonkey = "PythonPath"
pythonpath = "%s;%s\\Lib\\;%s\\DLLs\\" % (
  installpath, installpath, installpath
)
 
def RegisterPy():
  
  try:
    reg = OpenKey(HKEY_CURRENT_USER, regpath)
  except EnvironmentError as e:
    try:
      reg = CreateKey(HKEY_CURRENT_USER, regpath)
      SetValue(reg, installkey, REG_SZ, installpath)
      SetValue(reg, pythonkey, REG_SZ, pythonpath)
      CloseKey(reg)
    except:
      print ("*** Unable to register!")
      return
    print ("--- Python", version, "is now registered!")
    return
  if (QueryValue(reg, installkey) == installpath and
    QueryValue(reg, pythonkey) == pythonpath):
    CloseKey(reg)
    print ("=== Python", version, "is already registered!")
    return
  CloseKey(reg)
  print ("*** Unable to register!")
  print ("*** You probably have another Python installation!")
 
RegisterPy()

py –m pip install nltk

>import nltk
>nltk.download()

>from nltk.book import *