IRSwap does not round trip. IRSwap.from_dict(swap.as_dict()) throws type error

[AlexanderJHall]

When attempting to round trip an unresolved IRSwap instrument a TypeError is thrown.

The issue is not with IRSwap instrument but the way that the "Base" classes method __from_dict() handles datetime.dates. In 0.8.149 setting a instrument property to a datetime and then attempting to roundtrip via Instrument.from_dict(inst.as_dict()) will fail as Base.__from_dict() cannot handle datetime.date inputs.

To Reproduce
import datetime
from gs_quant.instrument import IRSwap
swap = IRSwap('Pay', termination_date=datetime.date(2030, 1, 2), fixed_rate='atm', notional_currency='eur')
swap.as_dict()
new_swap = IRSwap.from_dict(swap.as_dict())

Expected behavior
new_swap should be a new IRSwap instrument.

This used to work as expected in prior versions, eg 0.8.90.

Screenshots
If applicable, add screenshots to help explain your problem.

Systems setup:

• OS: Windows 10
• Python version 3.7
• GS-Quant version 0.8.149

Additional context
Error is:
File "", line 7, in
IRSwap.from_dict(swap.as_dict())
File "C:\Users\alexa\Anaconda3\lib\site-packages\gs_quant\instrument\core.py", line 55, in from_dict
return cls._from_dict(values)
File "C:\Users\alexa\Anaconda3\lib\site-packages\gs_quant\base.py", line 330, in _from_dict
instance.__from_dict(values)
File "C:\Users\alexa\Anaconda3\lib\site-packages\gs_quant\base.py", line 282, in __from_dict
setattr(self, prop, dateutil.parser.isoparse(prop_value).date())
File "C:\Users\alexa\Anaconda3\lib\site-packages\dateutil\parser\isoparser.py", line 37, in func
return f(self, str_in, *args, **kwargs)
File "C:\Users\alexa\Anaconda3\lib\site-packages\dateutil\parser\isoparser.py", line 134, in isoparse
components, pos = self._parse_isodate(dt_str)
File "C:\Users\alexa\Anaconda3\lib\site-packages\dateutil\parser\isoparser.py", line 208, in _parse_isodate
return self._parse_isodate_common(dt_str)
File "C:\Users\alexa\Anaconda3\lib\site-packages\dateutil\parser\isoparser.py", line 213, in _parse_isodate_common
len_str = len(dt_str)
TypeError: object of type 'datetime.date' has no len()

Issue is around line 280 of gs_quant.base.py:

elif issubclass(prop_type, dt.date):
try:
setattr(self, prop, dateutil.parser.isoparse(prop_value).date())
except ValueError:
if str in additional_types:
setattr(self, prop, prop_value)

suggest the except clause should be extended to include TypeError

This didn't occur in earlier versions of gs_quant as in this case prop_type (line 259) evaluated to None so this section of code ran:
if prop_type is None:
# This shouldn't happen
setattr(self, prop, prop_value)