FrRead.read_timeseries incompatible with python 3

Using an example from the docstring for FrRead, an error is raised while on Python 3.6.5. This looks like a python 3 incompatibility issue. FrRead needs to be used in gwcelery, which requires Python >3.5.

Python 3.6.5 |Anaconda, Inc.| (default, Apr 29 2018, 16:14:56) 
[GCC 7.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from lalframe import frread
>>> help(frread)

>>> out = frread.read_timeseries('L-R-1061499968-32.gwf', 'L1:PSL-ODC_CHANNEL_OUT_DQ')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/geoffrey.mo/.local/lib/python3.6/site-packages/lalframe/frread.py", line 122, in read_timeseries
    if isinstance(channel, (str, unicode)):
NameError: name 'unicode' is not defined