Clarify typing of _tostring_method.

Author: wRAR

parsel/selector.py

@@ -8,6 +8,7 @@
     Any,
     Dict,
     List,
+    Literal,
     Mapping,
     Optional,
     Pattern,
@@ -32,6 +33,10 @@
 
 _SelectorType = TypeVar("_SelectorType", bound="Selector")
 _ParserType = Union[etree.XMLParser, etree.HTMLParser]
+_TostringMethodType = Literal[  # simplified _OutputMethodArg from types-lxml
+    "html",
+    "xml",
+]
 
 lxml_version = parse_version(etree.__version__)
 lxml_huge_tree_version = parse_version("4.2")
@@ -341,8 +346,8 @@ def __init__(
         self._csstranslator: OriginalGenericTranslator = typing.cast(
             OriginalGenericTranslator, _ctgroup[st]["_csstranslator"]
         )
-        self._tostring_method: str = typing.cast(
-            str, _ctgroup[st]["_tostring_method"]
+        self._tostring_method: _TostringMethodType = typing.cast(
+            _TostringMethodType, _ctgroup[st]["_tostring_method"]
         )
 
         if text is not None:
@@ -508,14 +513,11 @@ def get(self) -> str:
         Percent encoded content is unquoted.
         """
         try:
-            return typing.cast(
-                str,
-                etree.tostring(
-                    self.root,
-                    method=self._tostring_method,
-                    encoding="unicode",
-                    with_tail=False,
-                ),
+            return etree.tostring(
+                self.root,
+                method=self._tostring_method,
+                encoding="unicode",
+                with_tail=False,
             )
         except (AttributeError, TypeError):
             if self.root is True: