JSONDecodeError raised when using README example

[reece]

When trying the example in the repo's README.md, I get:

>>> import genomelink                                                                                                                                 
>>> report = genomelink.Report.fetch(name='eye-color', population='european', token='GENOMELINKTEST')                                                 
Traceback (most recent call last):
  File "<ipython-input-5-73346705992d>", line 1, in <module>
    report = genomelink.Report.fetch(name='eye-color', population='european', token='GENOMELINKTEST')
  File "/home/reece/.virtualenvs/default-3.7/lib/python3.7/site-packages/genomelink/resource/report.py", line 33, in fetch
    record = Report(response.json())
  File "/home/reece/.virtualenvs/default-3.7/lib/python3.7/site-packages/requests/models.py", line 897, in json
    return complexjson.loads(self.text, **kwargs)
  File "/usr/lib/python3.7/json/__init__.py", line 348, in loads
    return _default_decoder.decode(s)
  File "/usr/lib/python3.7/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/lib/python3.7/json/decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
JSONDecodeError: Expecting value
>>> sys.version                                                                                                                                       
'3.7.1 (default, Oct 22 2018, 11:21:55) \n[GCC 8.2.0]'

The same occurs for Python 3.6.