blpapi in python version 3.9

I am trying to install the blpapi in python version 3.9

For the record i am able to get 3.7 and 3.8 working using the standard setup and running the pip command at the bottom of this page:

www.bloomberg.com/professional/support/api-library

The only modifications that i needed to make were:

for version 3.7:

py -3.7 -m pip install --index-url=https://bloomberg.bintray.com/pip/simple blpapi

for version 3.8:

py -3.8 -m pip install --index-url=https://bloomberg.bintray.com/pip/simple blpapi

I try exactly the same method for 3.9 but this throws an error:

py -3.9 -m pip install --index-url=https://bloomberg.bintray.com/pip/simple blpapi

This is the error:

Looking in indexes: https://bloomberg.bintray.com/pip/simple
Collecting blpapi
  Downloading https://bloomberg.bintray.com/pip/simple/blpapi/blpapi-3.15.2.tar.gz (229 kB)
     |████████████████████████████████| 229 kB 3.3 MB/s
    ERROR: Command errored out with exit status 1:
     command: 'C:\Python39\python.exe' -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'C:\\Users\\darren\\AppData\\Local\\Temp\\pip-install-ldwe3a4a\\blpapi\\setup.py'"'"'; __file__='"'"'C:\\Users\\darren\\AppData\\Local\\Temp\\pip-install-ldwe3a4a\\blpapi\\setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base 'C:\Users\darren\AppData\Local\Temp\pip-pip-egg-info-ehpqfebq'
         cwd: C:\Users\darren\AppData\Local\Temp\pip-install-ldwe3a4a\blpapi\
    Complete output (5 lines):
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "C:\Users\darren\AppData\Local\Temp\pip-install-ldwe3a4a\blpapi\setup.py", line 54, in <module>
        assert blpapiRoot or (blpapiIncludesVar and blpapiLibVar), \
    AssertionError: BLPAPI_ROOT (or BLPAPI_INCDIR/BLPAPI_LIBDIR) environment variable isn't defined
    ----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.

I tried searching for solutions for AssertionError: BLPAPI_ROOT (or BLPAPI_INCDIR/BLPAPI_LIBDIR) environment variable isn't defined but don't find anything that works and at this point am stuck.

Here is my basic code:

import os
import sys
#import xbbg

# check python version
if sys.version_info.major == 3:
    if sys.version_info.minor == 7:
        print('using version: 3.7')
        import blpapi

if sys.version_info.major == 3:
    if sys.version_info.minor == 8:
        print('using version: 3.8')
        with os.add_dll_directory('c:/blp/DAPI'):
            import blpapi


if sys.version_info >= (3,9):
    print('using version: 3.9')
    print('version 3.9 and above not working')
    sys.exit(0) # i added this to exit before the error message for v 3.9
    with os.add_dll_directory('c:/blp/DAPI'):
        import blpapi




x = 'hello world'
print(x)

Can anyone solve this please ?

(ideally having blpapi working with all versions).

Appears as though it is now supported whereas at the time of writing the question it was not:

We support and provide wheels for Python 2.7, 3.6, 3.7, 3.8 and 3.9; Both 32 and 64 bits, for Windows, macOS, and most versions of Linux. These wheels now come bundled with the required C++ API, and a separate C++ API installation is no longer required.

The link is here: https://www.bloomberg.com/professional/support/api-library/