diff --git a/src/anthropic/_utils/_utils.py b/src/anthropic/_utils/_utils.py
index d2bfc91a..83f88cc3 100644
--- a/src/anthropic/_utils/_utils.py
+++ b/src/anthropic/_utils/_utils.py
@@ -230,7 +230,7 @@ def human_join(seq: Sequence[str], *, delim: str = ", ", final: str = "or") -> s
 
 def quote(string: str) -> str:
     """Add single quotation marks around the given string. Does *not* do any escaping."""
-    return "'" + string + "'"
+    return f"'{string}'"
 
 
 def required_args(*variants: Sequence[str]) -> Callable[[CallableT], CallableT]:
diff --git a/tests/test_required_args.py b/tests/test_required_args.py
index c506e4ef..fc774314 100644
--- a/tests/test_required_args.py
+++ b/tests/test_required_args.py
@@ -43,7 +43,7 @@ def foo(*, a: str | None = None) -> str | None:
 def test_multiple_params() -> None:
     @required_args(["a", "b", "c"])
     def foo(a: str = "", *, b: str = "", c: str = "") -> str | None:
-        return a + " " + b + " " + c
+        return f"{a} {b} {c}"
 
     assert foo(a="a", b="b", c="c") == "a b c"