gistfile1.txt

from owslib.csw import CatalogueServiceWeb
csw = CatalogueServiceWeb('http://nationaalgeoregister.nl/geonetwork/srv/dut/csw')
csw.getrecords2()
print csw.results

Barts-MacBook-Air:tmp bartvandeneijnden$ python test.py 
0.8.4
Traceback (most recent call last):
  File "test.py", line 5, in <module>
    csw.getrecords2()
  File "/Library/Python/2.7/site-packages/owslib/csw.py", line 341, in getrecords2
    self._invoke()
  File "/Library/Python/2.7/site-packages/owslib/csw.py", line 605, in _invoke
    raise ows.ExceptionReport(self._exml, self.owscommon.namespace)
owslib.ows.ExceptionReport: 'invalid value'