Pickle protocol incompatible with Python 2.7 when reading in files

There is an issue when trying to read in results with Python 2. If you run:

import tupak
results = tupak.result.read_in_result('outdir', 'basic_tutorial')

You will get this error:

Traceback (most recent call last):
  File "/home/moritz/opt/pycharm-2018.1.2/helpers/pydev/pydev_run_in_console.py", line 52, in run_file
    pydev_imports.execfile(file, globals, locals)  # execute the script
  File "/home/moritz/Dropbox/PhD/PythonProjects/Tupak/tupak/examples/injection_examples/test_result_loading.py", line 6, in <module>
    results = tupak.result.read_in_result(outdir, label)
  File "/home/moritz/Dropbox/PhD/PythonProjects/Tupak/tupak/tupak/result.py", line 24, in read_in_result
    return Result(deepdish.io.load(filename))
  File "/home/moritz/.local/lib/python2.7/site-packages/deepdish/io/hdf5io.py", line 656, in load
    pathtable=pathtable)
  File "/home/moritz/.local/lib/python2.7/site-packages/deepdish/io/hdf5io.py", line 319, in _load_specific_level
    return _load_level(handler, getattr(grp, vv[0]), pathtable)
  File "/home/moritz/.local/lib/python2.7/site-packages/deepdish/io/hdf5io.py", line 482, in _load_level
    pathname)
  File "/home/moritz/.local/lib/python2.7/site-packages/deepdish/io/hdf5io.py", line 370, in _load_nonlink_level
    lev = _load_level(handler, grp, pathtable)
  File "/home/moritz/.local/lib/python2.7/site-packages/deepdish/io/hdf5io.py", line 482, in _load_level
    pathname)
  File "/home/moritz/.local/lib/python2.7/site-packages/deepdish/io/hdf5io.py", line 370, in _load_nonlink_level
    lev = _load_level(handler, grp, pathtable)
  File "/home/moritz/.local/lib/python2.7/site-packages/deepdish/io/hdf5io.py", line 482, in _load_level
    pathname)
  File "/home/moritz/.local/lib/python2.7/site-packages/deepdish/io/hdf5io.py", line 437, in _load_nonlink_level
    return _load_pickled(level)
  File "/home/moritz/.local/lib/python2.7/site-packages/deepdish/io/hdf5io.py", line 343, in _load_pickled
    if isinstance(level[0], ForcePickle):
  File "/home/moritz/.local/lib/python2.7/site-packages/tables/vlarray.py", line 681, in __getitem__
    return self.read(start, stop, step)[0]
  File "/home/moritz/.local/lib/python2.7/site-packages/tables/vlarray.py", line 825, in read
    outlistarr = [atom.fromarray(arr) for arr in listarr]
  File "/home/moritz/.local/lib/python2.7/site-packages/tables/atom.py", line 1228, in fromarray
    return six.moves.cPickle.loads(array.tostring())
ValueError: unsupported pickle protocol: 4

The issue is that this pickle protocol is simply not implemented for Python 2.