[+] improve emcont wrapper

deps/test-task-2025-06-30-v1/python/online/fxreader/pr34/test_task_2025_06_30_v1/tickers_retrieval/emcont.py

@@ -1,14 +1,62 @@
 import aiohttp
+import decimal
+import pydantic
 import json
 
-from typing import (Any,)
+from typing import (Any, Annotated, Optional,)
 
 class Emcont:
+	class rates_get_t:
+		class data_t(pydantic.BaseModel):
+			class rate_t(pydantic.BaseModel):
+				symbol: Annotated[
+					str,
+					pydantic.Field(
+						alias='Symbol',
+					)
+				]
+				bid: Annotated[
+					decimal.Decimal,
+					pydantic.Field(
+						alias='Bid',
+					)
+				]
+				ask: Annotated[
+					decimal.Decimal,
+					pydantic.Field(
+						alias='Ask',
+					)
+				]
+				product_type: Annotated[
+					str,
+					pydantic.Field(
+						alias='ProductType',
+					)
+				]
+			rates: Annotated[
+				list[rate_t],
+				pydantic.Field(
+					alias='Rates',
+				)
+			]
+
 	@classmethod
 	async def rates_get(
 		cls,
+		only_symbols: Optional[set[str]] = None,
 	) -> Any:
 		async with aiohttp.ClientSession() as session:
 			async with session.get('https://rates.emcont.com') as response:
-				data = await response.text()
+				data_json = await response.text()
-				return json.loads(data[5:-3])
+				data = cls.rates_get_t.data_t.model_validate_json(
+					data_json[5:-3],
+				)
+
+				if only_symbols:
+					data.rates = [
+						o
+						for o in data.rates
+						if o.symbol in only_symbols
+					]
+
+				return data