base64: arguments can be None (#4020)

Co-authored-by: hauntsaninja <>

stdlib/2and3/base64.pyi

@@ -1,6 +1,6 @@
 # Stubs for base64
 
-from typing import IO, Union, Text
+from typing import IO, Optional, Text, Union
 import sys
 
 if sys.version_info < (3,):
@@ -10,8 +10,8 @@ else:
     _encodable = bytes
     _decodable = Union[bytes, str]
 
-def b64encode(s: _encodable, altchars: bytes = ...) -> bytes: ...
-def b64decode(s: _decodable, altchars: bytes = ...,
+def b64encode(s: _encodable, altchars: Optional[bytes] = ...) -> bytes: ...
+def b64decode(s: _decodable, altchars: Optional[bytes] = ...,
               validate: bool = ...) -> bytes: ...
 def standard_b64encode(s: _encodable) -> bytes: ...
 def standard_b64decode(s: _decodable) -> bytes: ...
@@ -19,7 +19,7 @@ def urlsafe_b64encode(s: _encodable) -> bytes: ...
 def urlsafe_b64decode(s: _decodable) -> bytes: ...
 def b32encode(s: _encodable) -> bytes: ...
 def b32decode(s: _decodable, casefold: bool = ...,
-              map01: bytes = ...) -> bytes: ...
+              map01: Optional[bytes] = ...) -> bytes: ...
 def b16encode(s: _encodable) -> bytes: ...
 def b16decode(s: _decodable, casefold: bool = ...) -> bytes: ...
 if sys.version_info >= (3, 4):

tests/stubtest_whitelists/py3_common.txt

@@ -31,9 +31,6 @@ asyncio.transports.WriteTransport.set_write_buffer_limits
 asyncio.transports._FlowControlMixin.set_write_buffer_limits
 asyncio.windows_events
 asyncio.windows_utils
-base64.b32decode
-base64.b64decode
-base64.b64encode
 bdb.Bdb.__init__
 builtins.WindowsError
 builtins.bytearray.__float__