7 files changed, 141 insertions, 126 deletions

diff --git a/searx/engines/duckduckgo_weather.py b/searx/engines/duckduckgo_weather.py
index 9fad1e546..4d52effcd 100644
--- a/searx/engines/duckduckgo_weather.py
+++ b/searx/engines/duckduckgo_weather.py
@@ -76,12 +76,12 @@ def _weather_data(location: weather.GeoLocation, data: dict[str, t.Any]):
 
     return EngineResults.types.WeatherAnswer.Item(
         location=location,
-        temperature=weather.Temperature(unit="°C", value=data['temperature']),
+        temperature=weather.Temperature(val=data['temperature'], unit="°C"),
         condition=WEATHERKIT_TO_CONDITION[data["conditionCode"]],
-        feels_like=weather.Temperature(unit="°C", value=data['temperatureApparent']),
+        feels_like=weather.Temperature(val=data['temperatureApparent'], unit="°C"),
         wind_from=weather.Compass(data["windDirection"]),
-        wind_speed=weather.WindSpeed(data["windSpeed"], unit="mi/h"),
-        pressure=weather.Pressure(data["pressure"], unit="hPa"),
+        wind_speed=weather.WindSpeed(val=data["windSpeed"], unit="mi/h"),
+        pressure=weather.Pressure(val=data["pressure"], unit="hPa"),
         humidity=weather.RelativeHumidity(data["humidity"] * 100),
         cloud_cover=data["cloudCover"] * 100,
     )
diff --git a/searx/engines/open_meteo.py b/searx/engines/open_meteo.py
index 31ada12b0..948996b3c 100644
--- a/searx/engines/open_meteo.py
+++ b/searx/engines/open_meteo.py
@@ -1,6 +1,8 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 """Open Meteo (weather)"""
 
+import typing as t
+
 from urllib.parse import urlencode
 from datetime import datetime
 
@@ -106,16 +108,16 @@ WMO_TO_CONDITION: dict[int, weather.WeatherConditionType] = {
 }
 
 
-def _weather_data(location: weather.GeoLocation, data: dict):
+def _weather_data(location: weather.GeoLocation, data: dict[str, t.Any]):
 
     return WeatherAnswer.Item(
         location=location,
-        temperature=weather.Temperature(unit="°C", value=data["temperature_2m"]),
+        temperature=weather.Temperature(val=data["temperature_2m"], unit="°C"),
         condition=WMO_TO_CONDITION[data["weather_code"]],
-        feels_like=weather.Temperature(unit="°C", value=data["apparent_temperature"]),
+        feels_like=weather.Temperature(val=data["apparent_temperature"], unit="°C"),
         wind_from=weather.Compass(data["wind_direction_10m"]),
-        wind_speed=weather.WindSpeed(data["wind_speed_10m"], unit="km/h"),
-        pressure=weather.Pressure(data["pressure_msl"], unit="hPa"),
+        wind_speed=weather.WindSpeed(val=data["wind_speed_10m"], unit="km/h"),
+        pressure=weather.Pressure(val=data["pressure_msl"], unit="hPa"),
         humidity=weather.RelativeHumidity(data["relative_humidity_2m"]),
         cloud_cover=data["cloud_cover"],
     )
diff --git a/searx/engines/wttr.py b/searx/engines/wttr.py
index aec4d1075..9c7f69b43 100644
--- a/searx/engines/wttr.py
+++ b/searx/engines/wttr.py
@@ -1,6 +1,8 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 """wttr.in (weather forecast service)"""
 
+import typing as t
+
 from urllib.parse import quote
 from datetime import datetime
 
@@ -80,19 +82,19 @@ def request(query, params):
     return params
 
 
-def _weather_data(location: weather.GeoLocation, data: dict):
+def _weather_data(location: weather.GeoLocation, data: dict[str, t.Any]):
     # the naming between different data objects is inconsitent, thus temp_C and
     # tempC are possible
     tempC: float = data.get("temp_C") or data.get("tempC")  # type: ignore
 
     return WeatherAnswer.Item(
         location=location,
-        temperature=weather.Temperature(unit="°C", value=tempC),
+        temperature=weather.Temperature(val=tempC, unit="°C"),
         condition=WWO_TO_CONDITION[data["weatherCode"]],
-        feels_like=weather.Temperature(unit="°C", value=data["FeelsLikeC"]),
+        feels_like=weather.Temperature(val=data["FeelsLikeC"], unit="°C"),
         wind_from=weather.Compass(int(data["winddirDegree"])),
-        wind_speed=weather.WindSpeed(data["windspeedKmph"], unit="km/h"),
-        pressure=weather.Pressure(data["pressure"], unit="hPa"),
+        wind_speed=weather.WindSpeed(val=data["windspeedKmph"], unit="km/h"),
+        pressure=weather.Pressure(val=data["pressure"], unit="hPa"),
         humidity=weather.RelativeHumidity(data["humidity"]),
         cloud_cover=data["cloudcover"],
     )
diff --git a/searx/plugins/_core.py b/searx/plugins/_core.py
index ef8e5cf46..4b9db076e 100644
--- a/searx/plugins/_core.py
+++ b/searx/plugins/_core.py
@@ -1,7 +1,6 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # pylint: disable=too-few-public-methods,missing-module-docstring
 
-
 __all__ = ["PluginInfo", "Plugin", "PluginCfg", "PluginStorage"]
 
 import abc
@@ -9,16 +8,17 @@ import importlib
 import inspect
 import logging
 import re
-import typing
-from collections.abc import Sequence
+
+import typing as t
+from collections.abc import Generator
 
 from dataclasses import dataclass, field
 
 from searx.extended_types import SXNG_Request
-from searx.result_types import Result
 
-if typing.TYPE_CHECKING:
+if t.TYPE_CHECKING:
     from searx.search import SearchWithPlugins
+    from searx.result_types import Result, EngineResults, LegacyResult  # pyright: ignore[reportPrivateLocalImportUsage]
     import flask
 
 log: logging.Logger = logging.getLogger("searx.plugins")
@@ -42,7 +42,7 @@ class PluginInfo:
     description: str
     """Short description of the *answerer*."""
 
-    preference_section: typing.Literal["general", "ui", "privacy", "query"] | None = "general"
+    preference_section: t.Literal["general", "ui", "privacy", "query"] | None = "general"
     """Section (tab/group) in the preferences where this plugin is shown to the
     user.
 
@@ -71,7 +71,7 @@ class Plugin(abc.ABC):
     id: str = ""
     """The ID (suffix) in the HTML form."""
 
-    active: typing.ClassVar[bool]
+    active: t.ClassVar[bool]
     """Plugin is enabled/disabled by default (:py:obj:`PluginCfg.active`)."""
 
     keywords: list[str] = []
@@ -109,7 +109,7 @@ class Plugin(abc.ABC):
             raise ValueError(f"plugin ID {self.id} contains invalid character (use lowercase ASCII)")
 
         if not getattr(self, "log", None):
-            pkg_name = inspect.getmodule(self.__class__).__package__  # type: ignore
+            pkg_name = inspect.getmodule(self.__class__).__package__  # pyright: ignore[reportOptionalMemberAccess]
             self.log = logging.getLogger(f"{pkg_name}.{self.id}")
 
     def __hash__(self) -> int:
@@ -120,7 +120,7 @@ class Plugin(abc.ABC):
 
         return id(self)
 
-    def __eq__(self, other: typing.Any):
+    def __eq__(self, other: t.Any):
         """py:obj:`Plugin` objects are equal if the hash values of the two
         objects are equal."""
 
@@ -146,7 +146,7 @@ class Plugin(abc.ABC):
         """
         return True
 
-    def on_result(self, request: SXNG_Request, search: "SearchWithPlugins", result: Result) -> bool:
+    def on_result(self, request: SXNG_Request, search: "SearchWithPlugins", result: "Result") -> bool:
         """Runs for each result of each engine and returns a boolean:
 
         - ``True`` to keep the result
@@ -166,7 +166,9 @@ class Plugin(abc.ABC):
         """
         return True
 
-    def post_search(self, request: SXNG_Request, search: "SearchWithPlugins") -> None | Sequence[Result]:
+    def post_search(
+        self, request: SXNG_Request, search: "SearchWithPlugins"
+    ) -> "None | list[Result | LegacyResult] | EngineResults":
         """Runs AFTER the search request.  Can return a list of
         :py:obj:`Result <searx.result_types._base.Result>` objects to be added to the
         final result list."""
@@ -196,7 +198,7 @@ class PluginStorage:
     def __init__(self):
         self.plugin_list = set()
 
-    def __iter__(self):
+    def __iter__(self) -> Generator[Plugin]:
         yield from self.plugin_list
 
     def __len__(self):
@@ -207,7 +209,7 @@ class PluginStorage:
 
         return [p.info for p in self.plugin_list]
 
-    def load_settings(self, cfg: dict[str, dict[str, typing.Any]]):
+    def load_settings(self, cfg: dict[str, dict[str, t.Any]]):
         """Load plugins configured in SearXNG's settings :ref:`settings
         plugins`."""
 
@@ -262,7 +264,7 @@ class PluginStorage:
                 break
         return ret
 
-    def on_result(self, request: SXNG_Request, search: "SearchWithPlugins", result: Result) -> bool:
+    def on_result(self, request: SXNG_Request, search: "SearchWithPlugins", result: "Result") -> bool:
 
         ret = True
         for plugin in [p for p in self.plugin_list if p.id in search.user_plugins]:
diff --git a/searx/plugins/time_zone.py b/searx/plugins/time_zone.py
index f54a9ce6c..9239a3fbc 100644
--- a/searx/plugins/time_zone.py
+++ b/searx/plugins/time_zone.py
@@ -1,12 +1,11 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # pylint: disable=missing-module-docstring
 
-from __future__ import annotations
 import typing as t
 
 import datetime
 
-from flask_babel import gettext  # type: ignore
+from flask_babel import gettext
 from searx.result_types import EngineResults
 from searx.weather import DateTime, GeoLocation
 
@@ -53,13 +52,13 @@ class SXNGPlugin(Plugin):
         search_term = " ".join(query_parts).strip()
 
         if not search_term:
-            date_time = DateTime(time=datetime.datetime.now())
+            date_time = DateTime(datetime.datetime.now())
             results.add(results.types.Answer(answer=date_time.l10n()))
             return results
 
         geo = GeoLocation.by_query(search_term=search_term)
         if geo:
-            date_time = DateTime(time=datetime.datetime.now(tz=geo.zoneinfo))
+            date_time = DateTime(datetime.datetime.now(tz=geo.zoneinfo))
             tz_name = geo.timezone.replace('_', ' ')
             results.add(
                 results.types.Answer(
diff --git a/searx/weather.py b/searx/weather.py
index c8f3cf973..30b5bfeee 100644
--- a/searx/weather.py
+++ b/searx/weather.py
@@ -14,11 +14,10 @@ __all__ = [
     "GeoLocation",
 ]
 
-import typing
+import typing as t
 
 import base64
 import datetime
-import dataclasses
 import zoneinfo
 
 from urllib.parse import quote_plus
@@ -27,7 +26,8 @@ import babel
 import babel.numbers
 import babel.dates
 import babel.languages
-import flask_babel
+import flask_babel  # pyright: ignore[reportMissingTypeStubs]
+import msgspec
 
 from searx import network
 from searx.cache import ExpireCache, ExpireCacheCfg
@@ -120,8 +120,7 @@ def symbol_url(condition: "WeatherConditionType") -> str | None:
     return data_url
 
 
-@dataclasses.dataclass
-class GeoLocation:
+class GeoLocation(msgspec.Struct, kw_only=True):
     """Minimal implementation of Geocoding."""
 
     # The type definition was based on the properties from the geocoding API of
@@ -176,6 +175,8 @@ class GeoLocation:
 
         ctx = "weather_geolocation_by_query"
         cache = get_WEATHER_DATA_CACHE()
+        # {'name': 'Berlin', 'latitude': 52.52437, 'longitude': 13.41053,
+        #  'elevation': 74.0, 'country_code': 'DE', 'timezone': 'Europe/Berlin'}
         geo_props = cache.get(search_term, ctx=ctx)
 
         if not geo_props:
@@ -194,15 +195,14 @@ class GeoLocation:
         if not results:
             raise ValueError(f"unknown geo location: '{search_term}'")
         location = results[0]
-        return {field.name: location[field.name] for field in dataclasses.fields(cls)}
+        return {field_name: location[field_name] for field_name in cls.__struct_fields__}
 
 
-DateTimeFormats = typing.Literal["full", "long", "medium", "short"]
-DateTimeLocaleTypes = typing.Literal["UI"]
+DateTimeFormats = t.Literal["full", "long", "medium", "short"]
+DateTimeLocaleTypes = t.Literal["UI"]
 
 
-@typing.final
-class DateTime:
+class DateTime(msgspec.Struct):
     """Class to represent date & time.  Essentially, it is a wrapper that
     conveniently combines :py:obj:`datetime.datetime` and
     :py:obj:`babel.dates.format_datetime`.  A conversion of time zones is not
@@ -216,8 +216,7 @@ class DateTime:
     as the value for the ``locale``.
     """
 
-    def __init__(self, time: datetime.datetime):
-        self.datetime = time
+    datetime: datetime.datetime
 
     def __str__(self):
         return self.l10n()
@@ -252,36 +251,35 @@ class DateTime:
         return babel.dates.format_date(self.datetime, format=fmt, locale=locale)
 
 
-@typing.final
-class Temperature:
+TemperatureUnits: t.TypeAlias = t.Literal["°C", "°F", "K"]
+
+
+class Temperature(msgspec.Struct, kw_only=True):
     """Class for converting temperature units and for string representation of
     measured values."""
 
-    si_name = "Q11579"
+    val: float
+    unit: TemperatureUnits
 
-    Units = typing.Literal["°C", "°F", "K"]
-    """Supported temperature units."""
+    si_name: t.ClassVar[str] = "Q11579"
+    units: t.ClassVar[list[str]] = list(t.get_args(TemperatureUnits))
 
-    units = list(typing.get_args(Units))
-
-    def __init__(self, value: float, unit: Units):
-        if unit not in self.units:
-            raise ValueError(f"invalid unit: {unit}")
-        self.si: float = convert_to_si(  # pylint: disable=invalid-name
-            si_name=self.si_name,
-            symbol=unit,
-            value=value,
-        )
+    def __post_init__(self):
+        if self.unit not in self.units:
+            raise ValueError(f"invalid unit: {self.unit}")
 
     def __str__(self):
         return self.l10n()
 
-    def value(self, unit: Units) -> float:
-        return convert_from_si(si_name=self.si_name, symbol=unit, value=self.si)
+    def value(self, unit: TemperatureUnits) -> float:
+        if unit == self.unit:
+            return self.val
+        si_val = convert_to_si(si_name=self.si_name, symbol=self.unit, value=self.val)
+        return convert_from_si(si_name=self.si_name, symbol=unit, value=si_val)
 
     def l10n(
         self,
-        unit: Units | None = None,
+        unit: TemperatureUnits | None = None,
         locale: babel.Locale | GeoLocation | None = None,
         template: str = "{value} {unit}",
         num_pattern: str = "#,##0",
@@ -320,33 +318,35 @@ class Temperature:
         return template.format(value=val_str, unit=unit)
 
 
-@typing.final
-class Pressure:
+PressureUnits: t.TypeAlias = t.Literal["Pa", "hPa", "cm Hg", "bar"]
+
+
+class Pressure(msgspec.Struct, kw_only=True):
     """Class for converting pressure units and for string representation of
     measured values."""
 
-    si_name = "Q44395"
-
-    Units = typing.Literal["Pa", "hPa", "cm Hg", "bar"]
-    """Supported units."""
+    val: float
+    unit: PressureUnits
 
-    units = list(typing.get_args(Units))
+    si_name: t.ClassVar[str] = "Q44395"
+    units: t.ClassVar[list[str]] = list(t.get_args(PressureUnits))
 
-    def __init__(self, value: float, unit: Units):
-        if unit not in self.units:
-            raise ValueError(f"invalid unit: {unit}")
-        # pylint: disable=invalid-name
-        self.si: float = convert_to_si(si_name=self.si_name, symbol=unit, value=value)
+    def __post_init__(self):
+        if self.unit not in self.units:
+            raise ValueError(f"invalid unit: {self.unit}")
 
     def __str__(self):
         return self.l10n()
 
-    def value(self, unit: Units) -> float:
-        return convert_from_si(si_name=self.si_name, symbol=unit, value=self.si)
+    def value(self, unit: PressureUnits) -> float:
+        if unit == self.unit:
+            return self.val
+        si_val = convert_to_si(si_name=self.si_name, symbol=self.unit, value=self.val)
+        return convert_from_si(si_name=self.si_name, symbol=unit, value=si_val)
 
     def l10n(
         self,
-        unit: Units | None = None,
+        unit: PressureUnits | None = None,
         locale: babel.Locale | GeoLocation | None = None,
         template: str = "{value} {unit}",
         num_pattern: str = "#,##0",
@@ -363,8 +363,10 @@ class Pressure:
         return template.format(value=val_str, unit=unit)
 
 
-@typing.final
-class WindSpeed:
+WindSpeedUnits: t.TypeAlias = t.Literal["m/s", "km/h", "kn", "mph", "mi/h", "Bft"]
+
+
+class WindSpeed(msgspec.Struct, kw_only=True):
     """Class for converting speed or velocity units and for string
     representation of measured values.
 
@@ -375,28 +377,28 @@ class WindSpeed:
        (55.6 m/s)
     """
 
-    si_name = "Q182429"
-
-    Units = typing.Literal["m/s", "km/h", "kn", "mph", "mi/h", "Bft"]
-    """Supported units."""
+    val: float
+    unit: WindSpeedUnits
 
-    units = list(typing.get_args(Units))
+    si_name: t.ClassVar[str] = "Q182429"
+    units: t.ClassVar[list[str]] = list(t.get_args(WindSpeedUnits))
 
-    def __init__(self, value: float, unit: Units):
-        if unit not in self.units:
-            raise ValueError(f"invalid unit: {unit}")
-        # pylint: disable=invalid-name
-        self.si: float = convert_to_si(si_name=self.si_name, symbol=unit, value=value)
+    def __post_init__(self):
+        if self.unit not in self.units:
+            raise ValueError(f"invalid unit: {self.unit}")
 
     def __str__(self):
         return self.l10n()
 
-    def value(self, unit: Units) -> float:
-        return convert_from_si(si_name=self.si_name, symbol=unit, value=self.si)
+    def value(self, unit: WindSpeedUnits) -> float:
+        if unit == self.unit:
+            return self.val
+        si_val = convert_to_si(si_name=self.si_name, symbol=self.unit, value=self.val)
+        return convert_from_si(si_name=self.si_name, symbol=unit, value=si_val)
 
     def l10n(
         self,
-        unit: Units | None = None,
+        unit: WindSpeedUnits | None = None,
         locale: babel.Locale | GeoLocation | None = None,
         template: str = "{value} {unit}",
         num_pattern: str = "#,##0",
@@ -413,23 +415,23 @@ class WindSpeed:
         return template.format(value=val_str, unit=unit)
 
 
-@typing.final
-class RelativeHumidity:
-    """Amount of relative humidity in the air. The unit is ``%``"""
+RelativeHumidityUnits: t.TypeAlias = t.Literal["%"]
+
 
-    Units = typing.Literal["%"]
-    """Supported unit."""
+class RelativeHumidity(msgspec.Struct):
+    """Amount of relative humidity in the air. The unit is ``%``"""
 
-    units = list(typing.get_args(Units))
+    val: float
 
-    def __init__(self, humidity: float):
-        self.humidity = humidity
+    # there exists only one unit (%) --> set "%" as the final value (constant)
+    unit: t.ClassVar["t.Final[RelativeHumidityUnits]"] = "%"
+    units: t.ClassVar[list[str]] = list(t.get_args(RelativeHumidityUnits))
 
     def __str__(self):
         return self.l10n()
 
     def value(self) -> float:
-        return self.humidity
+        return self.val
 
     def l10n(
         self,
@@ -447,45 +449,50 @@ class RelativeHumidity:
         return template.format(value=val_str, unit=unit)
 
 
-@typing.final
-class Compass:
-    """Class for converting compass points and azimuth values (360°)"""
+CompassPoint: t.TypeAlias = t.Literal[
+    "N", "NNE", "NE", "ENE", "E", "ESE", "SE", "SSE", "S", "SSW", "SW", "WSW", "W", "WNW", "NW", "NNW"
+]
+"""Compass point type definition"""
 
-    Units = typing.Literal["°", "Point"]
+CompassUnits: t.TypeAlias = t.Literal["°", "Point"]
 
-    Point = typing.Literal[
-        "N", "NNE", "NE", "ENE", "E", "ESE", "SE", "SSE", "S", "SSW", "SW", "WSW", "W", "WNW", "NW", "NNW"
-    ]
-    """Compass point type definition"""
 
-    TURN = 360.0
+class Compass(msgspec.Struct):
+    """Class for converting compass points and azimuth values (360°)"""
+
+    val: "float | int | CompassPoint"
+    unit: CompassUnits = "°"
+
+    TURN: t.ClassVar[float] = 360.0
     """Full turn (360°)"""
 
-    POINTS = list(typing.get_args(Point))
+    POINTS: t.ClassVar[list[CompassPoint]] = list(t.get_args(CompassPoint))
     """Compass points."""
 
-    RANGE = TURN / len(POINTS)
+    RANGE: t.ClassVar[float] = TURN / len(POINTS)
     """Angle sector of a compass point"""
 
-    def __init__(self, azimuth: float | int | Point):
-        if isinstance(azimuth, str):
-            if azimuth not in self.POINTS:
-                raise ValueError(f"Invalid compass point: {azimuth}")
-            azimuth = self.POINTS.index(azimuth) * self.RANGE
-        self.azimuth = azimuth % self.TURN
+    def __post_init__(self):
+        if isinstance(self.val, str):
+            if self.val not in self.POINTS:
+                raise ValueError(f"Invalid compass point: {self.val}")
+            self.val = self.POINTS.index(self.val) * self.RANGE
+
+        self.val = self.val % self.TURN
+        self.unit = "°"
 
     def __str__(self):
         return self.l10n()
 
-    def value(self, unit: Units):
-        if unit == "Point":
-            return self.point(self.azimuth)
+    def value(self, unit: CompassUnits):
+        if unit == "Point" and isinstance(self.val, float):
+            return self.point(self.val)
         if unit == "°":
-            return self.azimuth
+            return self.val
         raise ValueError(f"unknown unit: {unit}")
 
     @classmethod
-    def point(cls, azimuth: float | int) -> Point:
+    def point(cls, azimuth: float | int) -> CompassPoint:
         """Returns the compass point to an azimuth value."""
         azimuth = azimuth % cls.TURN
         # The angle sector of a compass point starts 1/2 sector range before
@@ -496,7 +503,7 @@ class Compass:
 
     def l10n(
         self,
-        unit: Units = "Point",
+        unit: CompassUnits = "Point",
         locale: babel.Locale | GeoLocation | None = None,
         template: str = "{value}{unit}",
         num_pattern: str = "#,##0",
@@ -514,7 +521,7 @@ class Compass:
         return template.format(value=val_str, unit=unit)
 
 
-WeatherConditionType = typing.Literal[
+WeatherConditionType = t.Literal[
     # The capitalized string goes into to i18n/l10n (en: "Clear sky" -> de: "wolkenloser Himmel")
     "clear sky",
     "partly cloudy",
@@ -632,7 +639,7 @@ YR_WEATHER_SYMBOL_MAP = {
 if __name__ == "__main__":
 
     # test: fetch all symbols of the type catalog ..
-    for c in typing.get_args(WeatherConditionType):
+    for c in t.get_args(WeatherConditionType):
         symbol_url(condition=c)
 
     _cache = get_WEATHER_DATA_CACHE()
diff --git a/searx/webutils.py b/searx/webutils.py
index e025c6b47..65fcdc10e 100644
--- a/searx/webutils.py
+++ b/searx/webutils.py
@@ -16,6 +16,7 @@ from typing import Iterable, List, Tuple, TYPE_CHECKING
 from io import StringIO
 from codecs import getincrementalencoder
 
+import msgspec
 from flask_babel import gettext, format_date  # type: ignore
 
 from searx import logger, get_setting
@@ -147,6 +148,8 @@ def write_csv_response(csv: CSVWriter, rc: "ResultContainer") -> None:  # pylint
 
 class JSONEncoder(json.JSONEncoder):  # pylint: disable=missing-class-docstring
     def default(self, o):
+        if isinstance(o, msgspec.Struct):
+            return msgspec.to_builtins(o)
         if isinstance(o, datetime):
             return o.isoformat()
         if isinstance(o, timedelta):