Do not suppress JSON decode exceptions

		add = (value and value[0] == '+')

		if add:

			value = value[1:]

		with suppress(ValueError):

		try:

			if value[0] in '[{"':

				value = json.loads(value)

		except (IndexError, ValueError) as exc:

			raise ValueError("""JSON decode error while decoding {}="{}": {}"""

					.format(name, value, exc))

		if cur and add:

			if __debug__:

				LOGGER.debug("adding %s to %s (= %s )", value, name, repr(cur))