Error output when pyradex.Radex.datapath is not set

self_datapath.py

➜  ~ unset RADEX_DATAPATH
➜  ~ echo $RADEX_DATAPATH
➜  ~ pylab
Python 2.7.12 |Anaconda 4.0.0 (x86_64)| (default, Jul  2 2016, 17:43:17)
Type "copyright", "credits" or "license" for more information.

IPython 4.1.2 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.
Using matplotlib backend: MacOSX

In [1]: import pyradex

In [2]: R = pyradex.Radex(species='oh2co-h2', abundance=1e-8, column=1e14, temperature=20)
WARNING: Did not find data file for species oh2co-h2 in path .  Downloading it. [pyradex.base_class]
---------------------------------------------------------------------------
OSError                                   Traceback (most recent call last)
<ipython-input-2-047ffb4fcbb5> in <module>()
----> 1 R = pyradex.Radex(species='oh2co-h2', abundance=1e-8, column=1e14, temperature=20)

/Users/tsrice/anaconda2/lib/python2.7/site-packages/pyradex/core.pyc in __init__(self, collider_densities, density, total_density, temperature, species, column, column_per_bin, tbackground, deltav, abundance, datapath, escapeProbGeom, outfile, logfile, debug, mu, source_area)
    290                 raise ValueError("Data path %s was not successfully stored;"
    291                                  " instead %s was." % (datapath,self.datapath))
--> 292         self.species = species
    293         if self.molpath == b'':
    294             raise ValueError("Must set a species name.")

/Users/tsrice/anaconda2/lib/python2.7/site-packages/pyradex/base_class.pyc in species(self, species)
    130                      "in path {1}.  Downloading it.".format(species,
    131                                                             self.datapath))
--> 132             utils.get_datafile(species, self.datapath)
    133             self.molpath = os.path.join(self.datapath,species+'.dat')
    134

/Users/tsrice/anaconda2/lib/python2.7/site-packages/pyradex/utils.pyc in get_datafile(species, savedir)
     42
     43     if not os.path.isdir(savedir):
---> 44         mkdir_p(savedir)
     45
     46     if not os.path.isfile(datapath):

/Users/tsrice/anaconda2/lib/python2.7/site-packages/pyradex/utils.pyc in mkdir_p(path)
     11     """ mkdir -p equivalent [used by get_datafile]"""
     12     try:
---> 13         os.makedirs(path)
     14     except OSError as exc: # Python >2.5
     15         if exc.errno == errno.EEXIST and os.path.isdir(path):

/Users/tsrice/anaconda2/lib/python2.7/os.pyc in makedirs(name, mode)
    155         if tail == curdir:           # xxx/newdir/. exists if xxx/newdir exists
    156             return
--> 157     mkdir(name, mode)
    158
    159 def removedirs(name):

OSError: [Errno 2] No such file or directory: ''