Add basic stub for characteristic (#771)

See https://characteristic.readthedocs.io/en/stable/

third_party/2and3/characteristic/__init__.pyi

@@ -0,0 +1,34 @@
+from typing import Sequence, Callable, Union, Any, Optional, AnyStr, TypeVar, Type
+
+def with_repr(attrs: Sequence[Union[AnyStr, Attribute]]) -> Callable[..., Any]: ...
+def with_cmp(attrs: Sequence[Union[AnyStr, Attribute]]) -> Callable[..., Any]: ...
+def with_init(attrs: Sequence[Union[AnyStr, Attribute]]) -> Callable[..., Any]: ...
+def immutable(attrs: Sequence[Union[AnyStr, Attribute]]) -> Callable[..., Any]: ...
+
+def strip_leading_underscores(attribute_name: AnyStr) -> AnyStr: ...
+
+NOTHING = Any
+
+T = TypeVar('T')
+
+def attributes(
+    attrs: Sequence[Union[AnyStr, Attribute]],
+    apply_with_cmp: bool = True,
+    apply_with_init: bool = True,
+    apply_with_repr: bool = True,
+    apply_immutable: bool = False,
+    store_attributes: Optional[Callable[[type, Attribute], Any]] = None,
+    **kw: Optional[dict]) -> Callable[[Type[T]], Type[T]]: ...
+
+class Attribute:
+    def __init__(
+        self,
+        name: AnyStr,
+        exclude_from_cmp: bool = False,
+        exclude_from_init: bool = False,
+        exclude_from_repr: bool = False,
+        exclude_from_immutable: bool = False,
+        default_value: Any = NOTHING,
+        default_factory: Optional[Callable[[None], Any]] = None,
+        instance_of: Optional[Any] = None,
+        init_aliaser: Optional[Callable[[AnyStr], AnyStr]] = strip_leading_underscores) -> None: ...