Use of Final for "const-ish" values.

src/appui/_formatting.py

@@ -1,8 +1,9 @@
 """
 Functions for formatting various data types into strings for the Stockyard application.
 """
+from typing import Final
 
-_NO_VALUE: str = "N/A"  # TODO Maybe use "" instead?
+_NO_VALUE: Final[str] = "N/A"  # TODO Maybe use "" instead?
 
 
 def as_percent(value: float | None) -> str:

src/appui/_quote_column_definitions.py

@@ -1,7 +1,7 @@
 """Definitions of the available columns for the quote table."""
 
 from math import inf
-from typing import Optional, TypeVar
+from typing import Final, Optional, TypeVar
 
 from ._enums import Justify
 from ._formatting import as_float, as_percent, as_shrunk_int
@@ -42,7 +42,7 @@ def _sign(v: T) -> int:
     return 1 if v > 0 else -1 if v < 0 else 0
 
 
-ALL_QUOTE_COLUMNS: dict[str, QuoteColumn] = {
+ALL_QUOTE_COLUMNS: Final[dict[str, QuoteColumn]] = {
     "ticker": (
         QuoteColumn(
             "Ticker",

src/appui/_quote_table.py

@@ -2,7 +2,7 @@
 This module contains the QuoteTable class which is a DataTable for displaying quotes.
 """
 
-from typing import Any, override
+from typing import Any, Final, override
 
 from rich.style import Style
 from rich.text import Text
@@ -17,8 +17,8 @@
 class QuoteTable(DataTable[Text]):
     """A DataTable for displaying quotes."""
 
-    _GAINING_COLOR: str = "#00DD00"
-    _LOSING_COLOR: str = "#DD0000"
+    _GAINING_COLOR: Final[str] = "#00DD00"
+    _LOSING_COLOR: Final[str] = "#DD0000"
 
     def __init__(self, state: QuoteTableState) -> None:
         super().__init__()

src/appui/quote_table_state.py

@@ -3,7 +3,7 @@
 import logging
 from threading import Lock, Thread
 from time import monotonic, sleep
-from typing import Any, Callable, Optional
+from typing import Any, Callable, Final, Optional
 
 from yfinance import YFinance, YQuote
 
@@ -15,16 +15,16 @@
 class QuoteTableState:
     """The state of the quote table."""
 
-    _TICKER_COLUMN_KEY: str = "ticker"
+    _TICKER_COLUMN_KEY: Final[str] = "ticker"
 
     # Default values
-    _DEFAULT_COLUMN_KEYS: list[str] = [
+    _DEFAULT_COLUMN_KEYS: Final[list[str]] = [
         "last",
         "change_percent",
         "volume",
         "market_cap",
     ]
-    _DEFAULT_QUOTES: list[str] = [
+    _DEFAULT_QUOTES: Final[list[str]] = [
         "AAPL",
         "F",
         "VT",
@@ -34,15 +34,15 @@ class QuoteTableState:
         "EURUSD=X",
         "BTC-USD",
     ]
-    _DEFAULT_SORT_DIRECTION: SortDirection = SortDirection.ASCENDING
-    _DEFAULT_QUERY_FREQUENCY: int = 60
+    _DEFAULT_SORT_DIRECTION: Final[SortDirection] = SortDirection.ASCENDING
+    _DEFAULT_QUERY_FREQUENCY: Final[int] = 60
 
     # Config file keys
-    _COLUMNS: str = "columns"
-    _SORT_COLUMN: str = "sort_column"
-    _SORT_DIRECTION: str = "sort_direction"
-    _QUOTES: str = "quotes"
-    _QUERY_FREQUENCY: str = "query_frequency"
+    _COLUMNS: Final[str] = "columns"
+    _SORT_COLUMN: Final[str] = "sort_column"
+    _SORT_DIRECTION: Final[str] = "sort_direction"
+    _QUOTES: Final[str] = "quotes"
+    _QUERY_FREQUENCY: Final[str] = "query_frequency"
 
     def __init__(self, yfin: YFinance) -> None:
         self._yfin: YFinance = yfin

src/appui/stockyardapp_state.py

@@ -1,7 +1,7 @@
 """The state of the whole stockyard application."""
 
 import logging
-from typing import Any, Optional
+from typing import Any, Final, Optional
 
 from yfinance import YFinance
 
@@ -13,7 +13,7 @@ class StockyardAppState:
     """The state of the Stockyard app."""
 
     # Human readable logging levels
-    _LOGGING_LEVELS: dict[int, str] = {
+    _LOGGING_LEVELS: Final[dict[int, str]] = {
         logging.NOTSET: "NOTSET",
         logging.DEBUG: "DEBUG",
         logging.INFO: "INFO",
@@ -23,13 +23,13 @@ class StockyardAppState:
     }
 
     # Default values
-    _DEFAULT_LOG_LEVEL: int = logging.INFO
-    _DEFAULT_TIME_FORMAT: TimeFormat = TimeFormat.TWENTY_FOUR_HOUR
+    _DEFAULT_LOG_LEVEL: Final[int] = logging.INFO
+    _DEFAULT_TIME_FORMAT: Final[TimeFormat] = TimeFormat.TWENTY_FOUR_HOUR
 
     # Config file keys
-    _QUOTE_TABLE: str = "quote_table"
-    _LOG_LEVEL: str = "log_level"
-    _TIME_FORMAT: str = "time_format"
+    _QUOTE_TABLE: Final[str] = "quote_table"
+    _LOG_LEVEL: Final[str] = "log_level"
+    _TIME_FORMAT: Final[str] = "time_format"
 
     def __init__(self, yfin: YFinance, *, title: str = "Stockyard") -> None:
         # Transient members

src/yfinance/_yclient.py

@@ -6,7 +6,7 @@
 import logging
 from datetime import datetime, timedelta
 from http.cookiejar import Cookie
-from typing import Any
+from typing import Any, Final
 from urllib.parse import parse_qs, urlencode, urlparse
 
 import requests
@@ -16,17 +16,19 @@
 class YClient:
     """Yahoo! Finance API client."""
 
-    _DEFAULT_HTTP_TIMEOUT: int = 80
-    _YAHOO_FINANCE_URL: str = "https://finance.yahoo.com"
-    _YAHOO_FINANCE_QUERY_URL: str = "https://query1.finance.yahoo.com"
-    _CRUMB_URL: str = _YAHOO_FINANCE_QUERY_URL + "/v1/test/getcrumb"
-    _USER_AGENT: str = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.0.0 Safari/537.36"  # noqa: E501
-    _USER_AGENT_CLIENT_HINT_BRANDING_AND_VERSION: str = (
-        '"Google Chrome";v="113", "Chromium";v="113", "Not-A.Brand";v="24"'
-    )
-    _USER_AGENT_CLIENT_HINT_PLATFORM: str = '"Windows"'
-
-    _COOKIE_HEADERS: dict[str, str] = {
+    _DEFAULT_HTTP_TIMEOUT: Final[int] = 80
+    _YAHOO_FINANCE_URL: Final[str] = "https://finance.yahoo.com"
+    _YAHOO_FINANCE_QUERY_URL: Final[str] = "https://query1.finance.yahoo.com"
+    _CRUMB_URL: Final[str] = _YAHOO_FINANCE_QUERY_URL + "/v1/test/getcrumb"
+    _USER_AGENT: Final[
+        str
+    ] = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.0.0 Safari/537.36"  # noqa: E501
+    _USER_AGENT_CLIENT_HINT_BRANDING_AND_VERSION: Final[
+        str
+    ] = '"Google Chrome";v="113", "Chromium";v="113", "Not-A.Brand";v="24"'
+    _USER_AGENT_CLIENT_HINT_PLATFORM: Final[str] = '"Windows"'
+
+    _COOKIE_HEADERS: Final[dict[str, str]] = {
         "authority": "finance.yahoo.com",
         "accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7",  # noqa: E501
         "accept-language": "en-US,en;q=0.9",

src/yfinance/yfinance.py

@@ -1,7 +1,7 @@
 """A Python interface to the Yahoo! Finance API."""
 
 import logging
-from typing import Any
+from typing import Any, Final
 
 from ._yclient import YClient
 from .yquote import YQuote
@@ -10,7 +10,7 @@
 class YFinance:
     """A Python interface to the Yahoo! Finance API."""
 
-    _QUOTE_API: str = "/v7/finance/quote"
+    _QUOTE_API: Final[str] = "/v7/finance/quote"
 
     def __init__(self) -> None:
         self._yclient = YClient()

tests/appui/test_quote_table_state.py

@@ -9,7 +9,7 @@
 import sys
 from contextlib import contextmanager
 from time import sleep
-from typing import Any
+from typing import Any, Final
 
 import pytest
 
@@ -21,13 +21,15 @@
 from .helpers import compare_shrunken_ints
 
 # A number with 2 decimal values
-NUMBER_RE: re.Pattern[str] = re.compile(r"^(?:-?\d+\.\d{2}|N/A)$", re.M)
+NUMBER_RE: Final[re.Pattern[str]] = re.compile(r"^(?:-?\d+\.\d{2}|N/A)$", re.M)
 
 # A percentage with 2 decimal values
-PERCENT_RE: re.Pattern[str] = re.compile(r"^(?:-?\d+\.\d{2}%|N/A)$", re.M)
+PERCENT_RE: Final[re.Pattern[str]] = re.compile(r"^(?:-?\d+\.\d{2}%|N/A)$", re.M)
 
 # A shrunken int
-SHRUNK_RE: re.Pattern[str] = re.compile(r"^(?:\d{1,3}(?:\.\d{2}[KMBT])?|N/A)$", re.M)
+SHRUNKEN_INT_RE: Final[re.Pattern[str]] = re.compile(
+    r"^(?:\d{1,3}(?:\.\d{2}[KMBT])?|N/A)$", re.M
+)
 
 
 @pytest.fixture(name="quote_table_state")
@@ -342,7 +344,7 @@ def test_default_get_quotes_rows(quote_table_state: QuoteTableState):
             assert row.values[0].value == quotes[i]
             assert NUMBER_RE.match(row.values[1].value)  # last
             assert PERCENT_RE.match(row.values[2].value)  # change_percent
-            assert SHRUNK_RE.match(row.values[3].value)  # market_cap
+            assert SHRUNKEN_INT_RE.match(row.values[3].value)  # market_cap
 
 
 ##############################################################################