apply black and isort (#4287)

* apply black and isort

* move some type ignores

stdlib/2and3/decimal.pyi

@@ -1,9 +1,7 @@
 import numbers
 import sys
 from types import TracebackType
-from typing import (
-    Any, Container, Dict, List, NamedTuple, Optional, overload, Sequence, Text, Tuple, Type, TypeVar, Union,
-)
+from typing import Any, Container, Dict, List, NamedTuple, Optional, Sequence, Text, Tuple, Type, TypeVar, Union, overload
 
 _Decimal = Union[Decimal, int]
 _DecimalNew = Union[Decimal, float, Text, Tuple[int, Sequence[int], int]]
@@ -11,7 +9,7 @@ if sys.version_info >= (3,):
     _ComparableNum = Union[Decimal, float, numbers.Rational]
 else:
     _ComparableNum = Union[Decimal, float]
-_DecimalT = TypeVar('_DecimalT', bound=Decimal)
+_DecimalT = TypeVar("_DecimalT", bound=Decimal)
 
 class DecimalTuple(NamedTuple):
     sign: int
@@ -39,27 +37,16 @@ class DecimalException(ArithmeticError):
         def handle(self, context: Context, *args: Any) -> Optional[Decimal]: ...
 
 class Clamped(DecimalException): ...
-
 class InvalidOperation(DecimalException): ...
-
 class ConversionSyntax(InvalidOperation): ...
-
 class DivisionByZero(DecimalException, ZeroDivisionError): ...
-
 class DivisionImpossible(InvalidOperation): ...
-
 class DivisionUndefined(InvalidOperation, ZeroDivisionError): ...
-
 class Inexact(DecimalException): ...
-
 class InvalidContext(InvalidOperation): ...
-
 class Rounded(DecimalException): ...
-
 class Subnormal(DecimalException): ...
-
 class Overflow(Inexact, Rounded): ...
-
 class Underflow(Inexact, Rounded, Subnormal): ...
 
 if sys.version_info >= (3,):
@@ -80,15 +67,12 @@ class Decimal(object):
         def __div__(self, other: _Decimal, context: Optional[Context] = ...) -> Decimal: ...
         def __rdiv__(self, other: _Decimal, context: Optional[Context] = ...) -> Decimal: ...
         def __ne__(self, other: object, context: Optional[Context] = ...) -> bool: ...
-
     def compare(self, other: _Decimal, context: Optional[Context] = ...) -> Decimal: ...
     def __hash__(self) -> int: ...
     def as_tuple(self) -> DecimalTuple: ...
     if sys.version_info >= (3, 6):
         def as_integer_ratio(self) -> Tuple[int, int]: ...
-
     def to_eng_string(self, context: Optional[Context] = ...) -> str: ...
-
     if sys.version_info >= (3,):
         def __abs__(self) -> Decimal: ...
         def __add__(self, other: _Decimal) -> Decimal: ...
@@ -139,9 +123,7 @@ class Decimal(object):
         def __str__(self, eng: bool = ..., context: Optional[Context] = ...) -> str: ...
         def __sub__(self, other: _Decimal, context: Optional[Context] = ...) -> Decimal: ...
         def __truediv__(self, other: _Decimal, context: Optional[Context] = ...) -> Decimal: ...
-
     def remainder_near(self, other: _Decimal, context: Optional[Context] = ...) -> Decimal: ...
-
     def __float__(self) -> float: ...
     def __int__(self) -> int: ...
     def __trunc__(self) -> int: ...
@@ -161,16 +143,15 @@ class Decimal(object):
     else:
         def __long__(self) -> long: ...
     def fma(self, other: _Decimal, third: _Decimal, context: Optional[Context] = ...) -> Decimal: ...
-
     def __rpow__(self, other: _Decimal, context: Optional[Context] = ...) -> Decimal: ...
     def normalize(self, context: Optional[Context] = ...) -> Decimal: ...
     if sys.version_info >= (3,):
-        def quantize(self, exp: _Decimal, rounding: Optional[str] = ...,
-                     context: Optional[Context] = ...) -> Decimal: ...
+        def quantize(self, exp: _Decimal, rounding: Optional[str] = ..., context: Optional[Context] = ...) -> Decimal: ...
         def same_quantum(self, other: _Decimal, context: Optional[Context] = ...) -> bool: ...
     else:
-        def quantize(self, exp: _Decimal, rounding: Optional[str] = ...,
-                     context: Optional[Context] = ..., watchexp: bool = ...) -> Decimal: ...
+        def quantize(
+            self, exp: _Decimal, rounding: Optional[str] = ..., context: Optional[Context] = ..., watchexp: bool = ...
+        ) -> Decimal: ...
         def same_quantum(self, other: _Decimal) -> bool: ...
     def to_integral_exact(self, rounding: Optional[str] = ..., context: Optional[Context] = ...) -> Decimal: ...
     def to_integral_value(self, rounding: Optional[str] = ..., context: Optional[Context] = ...) -> Decimal: ...
@@ -251,19 +232,31 @@ class Context(object):
     traps: Dict[_TrapType, bool]
     flags: Dict[_TrapType, bool]
     if sys.version_info >= (3,):
-        def __init__(self, prec: Optional[int] = ..., rounding: Optional[str] = ...,
-                     Emin: Optional[int] = ..., Emax: Optional[int] = ...,
-                     capitals: Optional[int] = ..., clamp: Optional[int] = ...,
-                     flags: Union[None, Dict[_TrapType, bool], Container[_TrapType]] = ...,
-                     traps: Union[None, Dict[_TrapType, bool], Container[_TrapType]] = ...,
-                     _ignored_flags: Optional[List[_TrapType]] = ...) -> None: ...
+        def __init__(
+            self,
+            prec: Optional[int] = ...,
+            rounding: Optional[str] = ...,
+            Emin: Optional[int] = ...,
+            Emax: Optional[int] = ...,
+            capitals: Optional[int] = ...,
+            clamp: Optional[int] = ...,
+            flags: Union[None, Dict[_TrapType, bool], Container[_TrapType]] = ...,
+            traps: Union[None, Dict[_TrapType, bool], Container[_TrapType]] = ...,
+            _ignored_flags: Optional[List[_TrapType]] = ...,
+        ) -> None: ...
     else:
-        def __init__(self, prec: Optional[int] = ..., rounding: Optional[str] = ...,
-                     traps: Union[None, Dict[_TrapType, bool], Container[_TrapType]] = ...,
-                     flags: Union[None, Dict[_TrapType, bool], Container[_TrapType]] = ...,
-                     Emin: Optional[int] = ..., Emax: Optional[int] = ...,
-                     capitals: Optional[int] = ..., _clamp: Optional[int] = ...,
-                     _ignored_flags: Optional[List[_TrapType]] = ...) -> None: ...
+        def __init__(
+            self,
+            prec: Optional[int] = ...,
+            rounding: Optional[str] = ...,
+            traps: Union[None, Dict[_TrapType, bool], Container[_TrapType]] = ...,
+            flags: Union[None, Dict[_TrapType, bool], Container[_TrapType]] = ...,
+            Emin: Optional[int] = ...,
+            Emax: Optional[int] = ...,
+            capitals: Optional[int] = ...,
+            _clamp: Optional[int] = ...,
+            _ignored_flags: Optional[List[_TrapType]] = ...,
+        ) -> None: ...
     if sys.version_info >= (3,):
         # __setattr__() only allows to set a specific set of attributes,
         # already defined above.