CSV Import - 'NoneType' object is not iterable

When trying to import a CSV I get the following error:

Apr 19 15:08:34 dsgnmisp01 misp-modules: 2018-04-19 15:08:34,735 - misp-modules - ERROR - Something went wrong:
Apr 19 15:08:34 dsgnmisp01 misp-modules: Traceback (most recent call last):
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "/usr/lib/python3.4/site-packages/misp_modules/__init__.py", line 197, in post
Apr 19 15:08:34 dsgnmisp01 misp-modules: response = yield tornado.gen.with_timeout(timeout, self.run_request(jsonpayload))
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "/usr/lib64/python3.4/site-packages/tornado/gen.py", line 1099, in run
Apr 19 15:08:34 dsgnmisp01 misp-modules: value = future.result()
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "/usr/lib64/python3.4/asyncio/futures.py", line 274, in result
Apr 19 15:08:34 dsgnmisp01 misp-modules: raise self._exception
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "/usr/lib64/python3.4/concurrent/futures/thread.py", line 54, in run
Apr 19 15:08:34 dsgnmisp01 misp-modules: result = self.fn(*self.args, **self.kwargs)
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "/usr/lib/python3.4/site-packages/misp_modules/__init__.py", line 185, in run_request
Apr 19 15:08:34 dsgnmisp01 misp-modules: response = mhandlers[x['module']].handler(q=jsonpayload)
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "modules/import_mod/csvimport.py", line 117, in handler
Apr 19 15:08:34 dsgnmisp01 misp-modules: csv_parser.parse_data(data.split('\n'))
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "modules/import_mod/csvimport.py", line 28, in parse_data
Apr 19 15:08:34 dsgnmisp01 misp-modules: self.delimiter, self.length = self.findDelimiter()
Apr 19 15:08:34 dsgnmisp01 misp-modules: TypeError: 'NoneType' object is not iterable
Apr 19 15:08:34 dsgnmisp01 misp-modules: ERROR:misp-modules:Something went wrong:
Apr 19 15:08:34 dsgnmisp01 misp-modules: Traceback (most recent call last):
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "/usr/lib/python3.4/site-packages/misp_modules/__init__.py", line 197, in post
Apr 19 15:08:34 dsgnmisp01 misp-modules: response = yield tornado.gen.with_timeout(timeout, self.run_request(jsonpayload))
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "/usr/lib64/python3.4/site-packages/tornado/gen.py", line 1099, in run
Apr 19 15:08:34 dsgnmisp01 misp-modules: value = future.result()
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "/usr/lib64/python3.4/asyncio/futures.py", line 274, in result
Apr 19 15:08:34 dsgnmisp01 misp-modules: raise self._exception
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "/usr/lib64/python3.4/concurrent/futures/thread.py", line 54, in run
Apr 19 15:08:34 dsgnmisp01 misp-modules: result = self.fn(*self.args, **self.kwargs)
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "/usr/lib/python3.4/site-packages/misp_modules/__init__.py", line 185, in run_request
Apr 19 15:08:34 dsgnmisp01 misp-modules: response = mhandlers[x['module']].handler(q=jsonpayload)
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "modules/import_mod/csvimport.py", line 117, in handler
Apr 19 15:08:34 dsgnmisp01 misp-modules: csv_parser.parse_data(data.split('\n'))
Apr 19 15:08:34 dsgnmisp01 misp-modules: File "modules/import_mod/csvimport.py", line 28, in parse_data
Apr 19 15:08:34 dsgnmisp01 misp-modules: self.delimiter, self.length = self.findDelimiter()
Apr 19 15:08:34 dsgnmisp01 misp-modules: TypeError: 'NoneType' object is not iterable

It seems something inside findDelimiter() is causing the issue.

Does someone have a working test.csv (with corresponding headers) I could troubleshoot with?

Start in modules/import_mod/csvimport.py, especially handler() and findDelimiter(), using the traceback as the entry point. Reproduce the failure with a CSV and its headers, then determine the expected delimiter and header handling; done means a valid CSV import no longer raises the reported NoneType iteration error.