Add missing argument types for xml.sax stubs (#3706)

* Add missing argument types for xml.sax stubs

* Fix xml typings

stdlib/2and3/xml/sax/saxutils.pyi

@@ -1,18 +1,23 @@
 import sys
-from typing import Mapping, Text
+from typing import Mapping, Text, Optional, Protocol, Union, TextIO
+from io import TextIOBase, RawIOBase
+from codecs import StreamWriter, StreamReaderWriter
 
 from xml.sax import handler
 from xml.sax import xmlreader
 
+class _Writable(Protocol):
+    def write(self, data: str) -> None: ...
+
 def escape(data: Text, entities: Mapping[Text, Text] = ...) -> Text: ...
 def unescape(data: Text, entities: Mapping[Text, Text] = ...) -> Text: ...
 def quoteattr(data: Text, entities: Mapping[Text, Text] = ...) -> Text: ...
 
 class XMLGenerator(handler.ContentHandler):
     if sys.version_info >= (3, 0):
-        def __init__(self, out=..., encoding=..., short_empty_elements: bool = ...) -> None: ...
+        def __init__(self, out: Optional[Union[TextIOBase, RawIOBase, StreamWriter, StreamReaderWriter, _Writable]] = ..., encoding: str = ..., short_empty_elements: bool = ...) -> None: ...
     else:
-        def __init__(self, out=..., encoding=...) -> None: ...
+        def __init__(self, out: Optional[Union[TextIOBase, RawIOBase, StreamWriter, StreamReaderWriter, _Writable]] = ..., encoding: str = ...) -> None: ...
     def startDocument(self): ...
     def endDocument(self): ...
     def startPrefixMapping(self, prefix, uri): ...
@@ -26,7 +31,7 @@ class XMLGenerator(handler.ContentHandler):
     def processingInstruction(self, target, data): ...
 
 class XMLFilterBase(xmlreader.XMLReader):
-    def __init__(self, parent=...) -> None: ...
+    def __init__(self, parent: Optional[xmlreader.XMLReader] = ...) -> None: ...
     def error(self, exception): ...
     def fatalError(self, exception): ...
     def warning(self, exception): ...

stdlib/2and3/xml/sax/xmlreader.pyi

@@ -1,3 +1,6 @@
+
+from typing import Tuple, Mapping, Optional
+
 class XMLReader:
     def __init__(self) -> None: ...
     def parse(self, source): ...
@@ -16,7 +19,7 @@ class XMLReader:
     def setProperty(self, name, value): ...
 
 class IncrementalParser(XMLReader):
-    def __init__(self, bufsize=...) -> None: ...
+    def __init__(self, bufsize: int = ...) -> None: ...
     def parse(self, source): ...
     def feed(self, data): ...
     def prepareParser(self, source): ...
@@ -30,7 +33,7 @@ class Locator:
     def getSystemId(self): ...
 
 class InputSource:
-    def __init__(self, system_id=...) -> None: ...
+    def __init__(self, system_id: Optional[str] = ...) -> None: ...
     def setPublicId(self, public_id): ...
     def getPublicId(self): ...
     def setSystemId(self, system_id): ...
@@ -43,7 +46,7 @@ class InputSource:
     def getCharacterStream(self): ...
 
 class AttributesImpl:
-    def __init__(self, attrs) -> None: ...
+    def __init__(self, attrs: Mapping[str, str]) -> None: ...
     def getLength(self): ...
     def getType(self, name): ...
     def getValue(self, name): ...
@@ -63,7 +66,7 @@ class AttributesImpl:
     def values(self): ...
 
 class AttributesNSImpl(AttributesImpl):
-    def __init__(self, attrs, qnames) -> None: ...
+    def __init__(self, attrs: Mapping[Tuple[str, str], str], qnames: Mapping[Tuple[str, str], str]) -> None: ...
     def getValueByQName(self, name): ...
     def getNameByQName(self, name): ...
     def getQNameByName(self, name): ...