System crash when no pairs exist in 'My Attributes' sorting

[hewgreen]

If you exhaust the pair nodes that exist in your 'My Attributes' list an error is raised rather than the 203 no content error being raised:

builtins.StopIteration
StopIteration

Traceback (most recent call last)
File "/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1997, in call
return self.wsgi_app(environ, start_response)
File "/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1985, in wsgi_app
response = self.handle_exception(e)
File "/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1540, in handle_exception
reraise(exc_type, exc_value, tb)
File "/anaconda3/lib/python3.6/site-packages/flask/_compat.py", line 33, in reraise
raise value
File "/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1982, in wsgi_app
response = self.full_dispatch_request()
File "/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1614, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1517, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/anaconda3/lib/python3.6/site-packages/flask/_compat.py", line 33, in reraise
raise value
File "/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1612, in full_dispatch_request
rv = self.dispatch_request()
File "/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1598, in dispatch_request
return self.view_functionsrule.endpoint
File "/Users/hewgreen/Google Drive/archive/biosamples/webappDev_BSDBCurator/curami/app/views.py", line 189, in attribute_curation_pair
results = get_next_pair_record(pair_id, sort_type, vioscreen_stop, specialism_attributes)
File "/Users/hewgreen/Google Drive/archive/biosamples/webappDev_BSDBCurator/curami/app/models.py", line 494, in get_next_pair_record
record = cursor.next()
File "/anaconda3/lib/python3.6/site-packages/py2neo/database/init.py", line 1382, in next
return self.next()
File "/anaconda3/lib/python3.6/site-packages/py2neo/database/init.py", line 1363, in next
raise StopIteration()
StopIteration