Apply typing to all of pre-commit-hooks

pre_commit_hooks/debug_statement_hook.py

@@ -5,6 +5,9 @@ import argparse
 import ast
 import collections
 import traceback
+from typing import List
+from typing import Optional
+from typing import Sequence
 
 
 DEBUG_STATEMENTS = {'pdb', 'ipdb', 'pudb', 'q', 'rdb'}
@@ -12,21 +15,21 @@ Debug = collections.namedtuple('Debug', ('line', 'col', 'name', 'reason'))
 
 
 class DebugStatementParser(ast.NodeVisitor):
-    def __init__(self):
-        self.breakpoints = []
+    def __init__(self):  # type: () -> None
+        self.breakpoints = []  # type: List[Debug]
 
-    def visit_Import(self, node):
+    def visit_Import(self, node):  # type: (ast.Import) -> None
         for name in node.names:
             if name.name in DEBUG_STATEMENTS:
                 st = Debug(node.lineno, node.col_offset, name.name, 'imported')
                 self.breakpoints.append(st)
 
-    def visit_ImportFrom(self, node):
+    def visit_ImportFrom(self, node):  # type: (ast.ImportFrom) -> None
         if node.module in DEBUG_STATEMENTS:
             st = Debug(node.lineno, node.col_offset, node.module, 'imported')
             self.breakpoints.append(st)
 
-    def visit_Call(self, node):
+    def visit_Call(self, node):  # type: (ast.Call) -> None
         """python3.7+ breakpoint()"""
         if isinstance(node.func, ast.Name) and node.func.id == 'breakpoint':
             st = Debug(node.lineno, node.col_offset, node.func.id, 'called')
@@ -34,7 +37,7 @@ class DebugStatementParser(ast.NodeVisitor):
         self.generic_visit(node)
 
 
-def check_file(filename):
+def check_file(filename):  # type: (str) -> int
     try:
         with open(filename, 'rb') as f:
             ast_obj = ast.parse(f.read(), filename=filename)
@@ -58,7 +61,7 @@ def check_file(filename):
     return int(bool(visitor.breakpoints))
 
 
-def main(argv=None):
+def main(argv=None):  # type: (Optional[Sequence[str]]) -> int
     parser = argparse.ArgumentParser()
     parser.add_argument('filenames', nargs='*', help='Filenames to run')
     args = parser.parse_args(argv)