[BUG] Dataset.get_data fails with string start_time/end_time

[theavey]

Describe the bug
Dataset.get_data fails with string start_time/end_time

To Reproduce

from gs_quant.data import Dataset

ds = Dataset("EDRVS_EXPIRY_INTRADAY_PREMIUM")

ds.get_data(
    assetId=[
        "MA067JXW39B5T8VS",
        "MA07M4WC9PY2FBFG",
        "MA09RV3TD3ZEAZY3",
        "MA0B74FZFBAMZMQP",
        "MA0CT27ED3K3JD04",
    ],
    start_time="2022-03-03T00:00:00+00:00",
    end_time="2022-03-03T23:59:59+00:00",
    limit=10_000,
    strikeReference=["spot", "forward", "normalized", "delta"],
)

Expected behavior
get back a dataframe of data with no exceptions

Screenshots
Seems unneeded

Systems setup:

• OS: Windows 10
• Python version: '3.8.12 | packaged by conda-forge | (default, Oct 12 2021, 21:22:46) [MSC v.1916 64 bit (AMD64)]'
• GS-Quant version: '0.9.9'

Additional context
below is the stack trace. Didn't dig into your code fully, but seems to expect a timestamp, not a string, though does work if I pass in pd.Timestamps:

ds.get_data(
    assetId=[
        "MA067JXW39B5T8VS",
        "MA07M4WC9PY2FBFG",
        "MA09RV3TD3ZEAZY3",
        "MA0B74FZFBAMZMQP",
        "MA0CT27ED3K3JD04",
    ],
    start_time=pd.Timestamp("2022-03-03T00:00:00+00:00"),
    end_time=pd.Timestamp("2022-03-03T23:59:59+00:00"),
    limit=10_000,
    strikeReference=["spot", "forward", "normalized", "delta"],
)

TypeError Traceback (most recent call last)
Input In [7], in <cell line: 1>()
----> 1 ds.get_data(
2 assetId=[
3 "MA067JXW39B5T8VS",
4 "MA07M4WC9PY2FBFG",
5 "MA09RV3TD3ZEAZY3",
6 "MA0B74FZFBAMZMQP",
7 "MA0CT27ED3K3JD04",
8 ],
9 start_time="2022-03-03T00:00:00+00:00",
10 end_time="2022-03-03T23:59:59+00:00",
11 limit=10_000,
12 strikeReference=["spot", "forward", "normalized", "delta"],
13 )

File C:\ProgramData\Miniconda3\envs\t_env\lib\site-packages\gs_quant\data\dataset.py:122, in Dataset.get_data(self, start, end, as_of, since, fields, asset_id_type, **kwargs)
100 """
101 Get data for the given range and parameters
102
(...)
117 >>> weather_data = weather.get_data(dt.date(2016, 1, 15), dt.date(2016, 1, 16), city=('Boston', 'Austin'))
118 """
120 field_names = None if fields is None else list(map(lambda f: f if isinstance(f, str) else f.value, fields))
--> 122 query = self.provider.build_query(
123 start=start,
124 end=end,
125 as_of=as_of,
126 since=since,
127 fields=field_names,
128 **kwargs
129 )
130 data = self.provider.query_data(query, self.id, asset_id_type=asset_id_type)
132 return self.provider.construct_dataframe_with_types(self.id, data)

File C:\ProgramData\Miniconda3\envs\t_env\lib\site-packages\gs_quant\api\data.py:101, in DataApi.build_query(start, end, as_of, since, restrict_fields, format, dates, **kwargs)
99 snake_case_field = inflection.underscore(field)
100 if snake_case_field in query_properties:
--> 101 setattr(query, snake_case_field, value)
102 else:
103 query.where[field] = value

File C:\ProgramData\Miniconda3\envs\t_env\lib\site-packages\gs_quant\base.py:226, in Base.setattr(self, key, value)
223 raise ValueError(f'{key} cannot be set')
225 key = snake_case_key
--> 226 value = self.__coerce_value(fld.type, value)
227 self._property_changed(key, value)
228 elif key == 'name':

File C:\ProgramData\Miniconda3\envs\t_env\lib\site-packages\gs_quant\base.py:253, in Base.__coerce_value(cls, typ, value)
251 return value.to_dict()
252 if _is_supported_generic(typ):
--> 253 return _decode_generic(typ, value, False)
254 else:
255 return value

File C:\ProgramData\Miniconda3\envs\t_env\lib\site-packages\dataclasses_json\core.py:277, in decode_generic(type, value, infer_missing)
275 res = _decode_generic(type_arg, value, infer_missing)
276 else:
--> 277 res = _support_extended_types(type_arg, value)
278 else: # Union (already decoded or unsupported 'from_json' used)
279 res = value

File C:\ProgramData\Miniconda3\envs\t_env\lib\site-packages\dataclasses_json\core.py:220, in _support_extended_types(field_type, field_value)
218 else:
219 tz = datetime.now(timezone.utc).astimezone().tzinfo
--> 220 res = datetime.fromtimestamp(field_value, tz=tz)
221 elif _issubclass_safe(field_type, Decimal):
222 res = (field_value
223 if isinstance(field_value, Decimal)
224 else Decimal(field_value))

TypeError: an integer is required (got type str)