Remove unused import statements (#2282)

stdlib/3.4/_tracemalloc.pyi

@@ -3,7 +3,7 @@
 # for a more precise manual annotation of this module.
 # Feel free to edit the source below, but remove this header when you do.
 
-from typing import Any, List, Tuple, Dict, Generic
+from typing import Any
 
 def _get_object_traceback(*args, **kwargs) -> Any: ...
 

stdlib/3.4/enum.pyi

@@ -1,6 +1,6 @@
 # NB: third_party/3/enum.pyi and stdlib/3.4/enum.pyi must remain consistent!
 import sys
-from typing import List, Any, TypeVar, Union, Iterator, TypeVar, Generic, Type, Sized, Mapping
+from typing import Any, Iterator, List, Mapping, Type, TypeVar, Union
 from abc import ABCMeta
 
 _T = TypeVar('_T')

stdlib/3.4/tracemalloc.pyi

@@ -1,7 +1,7 @@
 # Stubs for tracemalloc (Python 3.4+)
 
 import sys
-from typing import Any, List, Optional, Sequence, Tuple, Union, overload
+from typing import List, Optional, Sequence, Tuple, Union, overload
 
 def clear_traces() -> None: ...
 def get_object_traceback(obj: object) -> Optional[Traceback]: ...