925,933c925,934
< try:
< # Use native type for those supported by JSON and
< # strings for everything else. skipkeys=True seems
< # to not work as well as one would hope
< if type(self._values[param].value) in \
< [str, unicode, int, long, float, bool, None]:
< d[param] = self._values[param].value
< else:
< d[param] = str(self._values[param])
---
> if value != None:
> try:
> # Use native type for those supported by JSON and
> # strings for everything else. skipkeys=True seems
> # to not work as well as one would hope
> if type(self._values[param].value) in \
> [str, unicode, int, long, float, bool, None]:
> d[param] = self._values[param].value
> else:
> d[param] = str(self._values[param])
935,936c936,937
< except AttributeError:
< pass
---
> except AttributeError:
> pass