diff --git a/src/pynyaa/_enums.py b/src/pynyaa/_enums.py
index f8ddeaf..1ad0daf 100644
--- a/src/pynyaa/_enums.py
+++ b/src/pynyaa/_enums.py
@@ -6,7 +6,7 @@
 
 from pynyaa._compat import IntEnum, StrEnum
 from pynyaa._types import CategoryID, CategoryLiteral, SortByLiteral
-from pynyaa._utils import get_category_id_from_name
+from pynyaa._utils import _get_category_id_from_name
 
 
 class BaseStrEnum(StrEnum):
@@ -17,7 +17,7 @@ def _missing_(cls, value: object) -> Self:
         for member in cls:
             if member.value.casefold() == str(value).casefold():
                 return member
-        message = f"'{value}' is not a valid {type(cls)}"
+        message = f"'{value}' is not a valid {cls.__name__}"
         raise ValueError(message)
 
 
@@ -63,7 +63,7 @@ def id(self) -> CategoryID:
         This ID corresponds to the category as seen in the URL
         `https://nyaa.si/?f=0&c=1_2&q=`, where `c=1_2` is the ID for `Anime - English-translated`.
         """
-        return get_category_id_from_name(self.value)
+        return _get_category_id_from_name(self.value)
 
     @overload
     @classmethod
diff --git a/src/pynyaa/_utils.py b/src/pynyaa/_utils.py
index 4f78984..cadd299 100644
--- a/src/pynyaa/_utils.py
+++ b/src/pynyaa/_utils.py
@@ -14,6 +14,8 @@
     P = ParamSpec("P")
     T = TypeVar("T")
 
+    # functools.cache destroys the signature of whatever it wraps, so we use this to fix it.
+    # This is to only "fool" typecheckers and IDEs, this doesn't exist at runtime.
     def cache(user_function: Callable[P, T], /) -> Callable[P, T]: ...  # type: ignore
 
 
@@ -22,16 +24,16 @@ def get_user_cache_path() -> Path:
 
 
 @overload
-def get_category_id_from_name(key: CategoryName) -> CategoryID: ...
+def _get_category_id_from_name(key: CategoryName) -> CategoryID: ...
 
 
 @overload
-def get_category_id_from_name(key: str) -> CategoryID: ...
+def _get_category_id_from_name(key: str) -> CategoryID: ...
 
 
 @cache
-def get_category_id_from_name(key: CategoryName | str) -> str:
-    mapping = {
+def _get_category_id_from_name(key: CategoryName | str) -> CategoryID:
+    mapping: dict[str, CategoryID] = {
         # All, c=0_0
         "All": "0_0",
         # Anime, c=1_X
diff --git a/tests/test_enums.py b/tests/test_enums.py
index 2d22e55..1089644 100644
--- a/tests/test_enums.py
+++ b/tests/test_enums.py
@@ -5,6 +5,16 @@
 from pynyaa import Category, Filter, SortBy
 
 
+def test_category_value_error() -> None:
+    with pytest.raises(ValueError):
+        Category.get("asdadadsad", "invalid default")
+
+
+def test_sortby_value_error() -> None:
+    with pytest.raises(ValueError):
+        SortBy.get("asdadadsad", "invalid default")
+
+
 @pytest.mark.parametrize(
     "category, expected_id",
     [