Graphenelib 0.6.4 and 0.6.5 erroneously handling PrivateKey

[bitphage]

#!/usr/bin/env python

#from bitsharesbase.account import PrivateKey
from graphenebase.account import PrivateKey

key = '6PRQdSDAjq41FVc58T1gykbihNPQeUCMWj8KW9uoeDKd1ZdZ6MbShYPhvS'

PrivateKey(key)
print('this should not happen')

Run testcase:

0.6.5:

this should not happen

0.6.3:

Traceback (most recent call last):
  File "./testcase2.py", line 8, in <module>
    PrivateKey(key)
  File "/home/vvk/.local/share/virtualenvs/DEXBot-XTl2tJdV/lib/python3.6/site-packages/graphenebase/account.py", line 322, in __init__
    self._pubkeyhex, self._pubkeyuncompressedhex = self.compressedpubkey()
  File "/home/vvk/.local/share/virtualenvs/DEXBot-XTl2tJdV/lib/python3.6/site-packages/graphenebase/account.py", line 331, in compressedpubkey
    order = ecdsa.SigningKey.from_string(secret, curve=ecdsa.SECP256k1).curve.generator.order()
  File "/home/vvk/.local/share/virtualenvs/DEXBot-XTl2tJdV/lib/python3.6/site-packages/ecdsa-0.13-py3.6.egg/ecdsa/keys.py", line 149, in from_string
    assert len(string) == curve.baselen, (len(string), curve.baselen)
AssertionError: (38, 32)