nordugrid-arc fails to build with Python 3.9.0a2.

[ERROR]
Traceback (most recent call last):
  File "./test_bloomfilter.py", line 47, in testReconstruction
    bf2 = bloomfilter.BloomFilter(SIZE, bits=bf1.serialize(), hashes=bf1.get_hashes())
  File "/builddir/build/BUILD/nordugrid-arc-6.4.1/src/services/acix/core/bloomfilter.py", line 107, in serialize
    return self.bits.tostring()
  File "/builddir/build/BUILD/nordugrid-arc-6.4.1/src/services/acix/core/bitvector.py", line 44, in tostring
    return self.bits.tostring()
builtins.AttributeError: 'array.array' object has no attribute 'tostring'
test_bloomfilter.BloomFilterTestCase.testReconstruction
===============================================================================
[ERROR]
Traceback (most recent call last):
  File "./test_bloomfilter.py", line 29, in testSerialization
    s = self.bf.serialize()
  File "/builddir/build/BUILD/nordugrid-arc-6.4.1/src/services/acix/core/bloomfilter.py", line 107, in serialize
    return self.bits.tostring()
  File "/builddir/build/BUILD/nordugrid-arc-6.4.1/src/services/acix/core/bitvector.py", line 44, in tostring
    return self.bits.tostring()
builtins.AttributeError: 'array.array' object has no attribute 'tostring'
test_bloomfilter.BloomFilterTestCase.testSerialization
-------------------------------------------------------------------------------
Ran 3 tests in 0.101s
FAILED (errors=2, successes=1)
FAIL: test_bloomfilter.py

See https://docs.python.org/3.9/whatsnew/3.9.html#removed

"array.array: tostring() and fromstring() methods have been removed. They were aliases to tobytes() and frombytes(), deprecated since Python 3.2."


For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.9/fedora-rawhide-x86_64/01170348-nordugrid-arc/

For all our attempts to build nordugrid-arc with Python 3.9, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.9/package/nordugrid-arc/

Testing and mass rebuild of packages is happening in copr. You can follow these instructions to test locally in mock if your package builds with Python 3.9:
https://copr.fedorainfracloud.org/coprs/g/python/python3.9/

Let us know here if you have any questions.

Python 3.9 will be included in Fedora 33. To make that update smoother, we're building Fedora packages with early pre-releases of Python 3.9.
A build failure prevents us from testing all dependent packages (transitive [Build]Requires), so if this package is required a lot, it's important for us to get it fixed soon.
We'd appreciate help from the people who know this package best, but if you don't want to work on this now, let us know so we can try to work around it on our side.