Merge branch 'V3/release/3.0.0' into V3/develop

# Conflicts:
#	redbot/cogs/customcom/customcom.py
#	redbot/core/errors.py

redbot/core/errors.py

@@ -1,4 +1,11 @@
 import importlib.machinery
+from typing import Optional
+
+import discord
+
+from .i18n import Translator
+
+_ = Translator(__name__, __file__)
 
 
 class RedError(Exception):
@@ -21,3 +28,24 @@ class CogLoadError(RedError):
     The message will be send to the user."""
 
     pass
+
+
+class BankError(RedError):
+    """Base error class for bank-related errors."""
+
+
+class BalanceTooHigh(BankError, OverflowError):
+    """Raised when trying to set a user's balance to higher than the maximum."""
+
+    def __init__(
+        self, user: discord.abc.User, max_balance: int, currency_name: str, *args, **kwargs
+    ):
+        super().__init__(*args, **kwargs)
+        self.user = user
+        self.max_balance = max_balance
+        self.currency_name = currency_name
+
+    def __str__(self) -> str:
+        return _("{user}'s balance cannot rise above {max:,} {currency}.").format(
+            user=self.user, max=self.max_balance, currency=self.currency_name
+        )