apply black and isort (#4287)

* apply black and isort

* move some type ignores

stdlib/2and3/struct.pyi

@@ -4,9 +4,9 @@
 # Based on http://docs.python.org/2/library/struct.html
 
 import sys
-from typing import Any, Tuple, Text, Union, Iterator
 from array import array
 from mmap import mmap
+from typing import Any, Iterator, Text, Tuple, Union
 
 class error(Exception): ...
 
@@ -22,6 +22,7 @@ def pack(fmt: _FmtType, *v: Any) -> bytes: ...
 def pack_into(fmt: _FmtType, buffer: _WriteBufferType, offset: int, *v: Any) -> None: ...
 def unpack(__format: _FmtType, __buffer: _BufferType) -> Tuple[Any, ...]: ...
 def unpack_from(__format: _FmtType, buffer: _BufferType, offset: int = ...) -> Tuple[Any, ...]: ...
+
 if sys.version_info >= (3, 4):
     def iter_unpack(__format: _FmtType, __buffer: _BufferType) -> Iterator[Tuple[Any, ...]]: ...
 
@@ -33,9 +34,7 @@ class Struct:
     else:
         format: bytes
     size: int
-
     def __init__(self, format: _FmtType) -> None: ...
-
     def pack(self, *v: Any) -> bytes: ...
     def pack_into(self, buffer: _WriteBufferType, offset: int, *v: Any) -> None: ...
     def unpack(self, __buffer: _BufferType) -> Tuple[Any, ...]: ...