tools: Use Python 3 syntax for typing in many files.

tools/lint

@@ -17,8 +17,7 @@ import lister
 from typing import cast, Callable, Dict, Iterator, List
 
 
-def run_parallel(lint_functions):
-    # type: (Dict[str, Callable[[], int]]) -> bool
+def run_parallel(lint_functions: Dict[str, Callable[[], int]]) -> bool:
     pids = []
     for name, func in lint_functions.items():
         pid = os.fork()
@@ -38,8 +37,7 @@ def run_parallel(lint_functions):
             failed = True
     return failed
 
-def run():
-    # type: () -> None
+def run() -> None:
     parser = argparse.ArgumentParser()
     parser.add_argument('--force', default=False,
                         action="store_true",
@@ -117,13 +115,11 @@ def run():
 
     lint_functions = {}  # type: Dict[str, Callable[[], int]]
 
-    def lint(func):
-        # type: (Callable[[], int]) -> Callable[[], int]
+    def lint(func: Callable[[], int]) -> Callable[[], int]:
         lint_functions[func.__name__] = func
         return func
 
-    def external_linter(name, command, target_langs=[]):
-        # type: (str, List[str], List[str]) -> None
+    def external_linter(name: str, command: List[str], target_langs: List[str]=[]) -> None:
         """Registers an external linter program to be run as part of the
         linter.  This program will be passed the subset of files being
         linted that have extensions in target_langs.  If there are no
@@ -133,8 +129,7 @@ def run():
         """
         color = next(colors)
 
-        def run_linter():
-            # type: () -> int
+        def run_linter() -> int:
             targets = []  # type: List[str]
             if len(target_langs) != 0:
                 targets = [target for lang in target_langs for target in by_lang[lang]]
@@ -172,26 +167,22 @@ def run():
     #     external_linter('commit_messages', ['tools/commit-message-lint'])
 
     @lint
-    def custom_py():
-        # type: () -> int
+    def custom_py() -> int:
         failed = check_custom_checks_py()
         return 1 if failed else 0
 
     @lint
-    def custom_nonpy():
-        # type: () -> int
+    def custom_nonpy() -> int:
         failed = check_custom_checks_nonpy()
         return 1 if failed else 0
 
     @lint
-    def pyflakes():
-        # type: () -> int
+    def pyflakes() -> int:
         failed = check_pyflakes(args, by_lang)
         return 1 if failed else 0
 
     @lint
-    def pep8():
-        # type: () -> int
+    def pep8() -> int:
         failed = check_pep8(by_lang['py'])
         return 1 if failed else 0