Enable typechecking for torch.testing._internal.common_quantized.* (pytorch#44805)

Summary:
Addresses a subproblem of [Issue 42969](pytorch#42969)

Pull Request resolved: pytorch#44805

Reviewed By: malfet

Differential Revision: D23742754

Pulled By: janeyx99

fbshipit-source-id: e916a6a0c049cac318549a485d47f19363087d15

Author: janeyx99

mypy.ini

@@ -62,9 +62,6 @@ ignore_errors = True
 [mypy-torch.testing._internal.codegen.*]
 ignore_errors = True
 
-[mypy-torch.testing._internal.common_quantized.*]
-ignore_errors = True
-
 [mypy-torch.testing._internal.jit_utils.*]
 ignore_errors = True
 

torch/backends/quantized/__init__.py

@@ -50,3 +50,5 @@ def __getattr__(self, attr):
 # This is the sys.modules replacement trick, see
 # https://stackoverflow.com/questions/2447353/getattr-on-a-module/7668273#7668273
 sys.modules[__name__] = QuantizedEngine(sys.modules[__name__], __name__)
+engine: str
+supported_engines: List[str]