Deprecated camelCase methods

Python prefers snake_case methods and camelCase classes. This replaces
some camelCase methods with snake_case variants, and has the original
names raise a DeprecationWarning before calling the snake_case versions

PLUGINS.md

@@ -227,7 +227,7 @@ a single set and two get methods, the new methods provide better type safety.
 **Be sure to use a unique prefix for any settings you save so as not to clash
 with core EDMC or other plugins.**
 
-Use `numberFromString()` from EDMC's `l10n.Locale` object to parse input
+Use `number_from_string()` from EDMC's `l10n.Locale` object to parse input
 numbers in a locale-independent way.
 
 Note that in the following example the function signature defines that it
@@ -288,7 +288,7 @@ For a more complicated item create a tk.Frame widget and populate it with other
 ttk widgets. Return `None` if you just want to use this as a callback after the
 main window and all other plugins are initialised.
 
-You can use `stringFromNumber()` from EDMC's `l10n.Locale` object to format
+You can use `string_from_number()` from EDMC's `l10n.Locale` object to format
 numbers in your widgets in a locale-independent way.
 
 ```python

l10n.py

@@ -13,6 +13,7 @@ from contextlib import suppress
 from os.path import basename, dirname, exists, isdir, isfile, join
 from sys import platform
 from typing import TYPE_CHECKING, Dict, Iterable, Optional, Set, TextIO, Union, cast
+import warnings
 
 if TYPE_CHECKING:
     def _(x: str) -> str: ...
@@ -93,7 +94,7 @@ class _Translations:
         available.add(_Translations.FALLBACK)
         if not lang:
             # Choose the default language
-            for preferred in Locale.preferredLanguages():
+            for preferred in Locale.preferred_languages():
                 components = preferred.split('-')
                 if preferred in available:
                     lang = preferred
@@ -246,7 +247,19 @@ class _Locale:
             self.float_formatter.setMinimumFractionDigits_(5)
             self.float_formatter.setMaximumFractionDigits_(5)
 
-    def stringFromNumber(self, number: Union[float, int], decimals: int = None) -> str:
+    def stringFromNumber(self, number: Union[float, int], decimals: int = None) -> str:  # noqa: N802
+        warnings.warn(DeprecationWarning('use _Locale.string_from_number instead.'))
+        return self.stringFromNumber(number, decimals)
+
+    def numberFromString(self, string: str) -> Union[int, float, None]:  # noqa: N802
+        warnings.warn(DeprecationWarning('use _Locale.number_from_string instead.'))
+        return self.numberFromString(string)
+
+    def preferredLanguages(self) -> Iterable[str]:  # noqa: N802
+        warnings.warn(DeprecationWarning('use _Locale.preferred_languages instead.'))
+        return self.preferred_languages()
+
+    def string_from_number(self, number: Union[float, int], decimals: int = None) -> str:
         """
         Convert a number to a string.
 
@@ -275,7 +288,7 @@ class _Locale:
         else:
             return locale.format('%.*f', (decimals, number), True)  # type: ignore  # It ends up working out
 
-    def numberFromString(self, string: str) -> Union[int, float, None]:
+    def number_from_string(self, string: str) -> Union[int, float, None]:
         """
         Convert a string to a number using the system locale.
 
@@ -294,7 +307,7 @@ class _Locale:
 
         return None
 
-    def preferredLanguages(self) -> Iterable[str]:
+    def preferred_languages(self) -> Iterable[str]:
         """
         Return a list of preferred language codes.
 

stats.py

@@ -448,4 +448,4 @@ class StatsResults(tk.Toplevel):
     def credits(self, value: int) -> str:
         """Localised string of given int, including a trailing ` Cr`."""
         # TODO: Locale is a class, this calls an instance method on it with an int as its `self`
-        return Locale.stringFromNumber(value, 0) + ' Cr'  # type: ignore
+        return Locale.string_from_number(value, 0) + ' Cr'  # type: ignore