Stream decrypt error

[arcsector]

Hello, I have been using pyaes for some time now, but I keep getting this error now when using decrypt_stream:

from pyaes import AESModeOfOperationCTR as ctr, encrypt_stream as es, decrypt_stream as ds
from yaml import load

credsdict = load(open("secrets.yml", 'r'))
key = credsdict['key'].encode('utf-8')
aes = ctr(key)
with open("secrets.yml", 'r') as file_in:
        with open('newsecrets','wb+') as file_out:
                es(aes, file_in, file_out)

newaes=ctr(key)
with open("newsecrets", 'r') as file_in:
        with open('newsecrets.yml', 'w+') as file_out:
                ds(newaes, file_in, file_out)
newdict = load(open('newsecrets.yml', 'r'))

It fails on the decryption with the following stack trace:

Traceback (most recent call last):
  File "createsecrets.py", line 28, in <module>
    ds(newaes, file_in, file_out)
  File "/usr/lib/python3.4/site-packages/pyaes/blockfeeder.py", line 227, in decrypt_stream
    _feed_stream(decrypter, in_stream, out_stream, block_size)
  File "/usr/lib/python3.4/site-packages/pyaes/blockfeeder.py", line 207, in _feed_stream
    chunk = in_stream.read(block_size)
  File "/usr/lib64/python3.4/codecs.py", line 319, in decode
    (result, consumed) = self._buffer_decode(data, self.errors, final)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xb2 in position 1: invalid start byte

Any tips? I've dealt with Unicode errors before but I can't seem to get this one to work...