Refactor various typing related issues

doc/how_tos/custom_checkers.rst

@@ -36,9 +36,11 @@ Firstly we will need to fill in some required boilerplate:
 .. code-block:: python
 
   import astroid
+  from astroid import nodes
 
   from pylint.checkers import BaseChecker
   from pylint.interfaces import IAstroidChecker
+  from pylint.lint import PyLinter
 
   class UniqueReturnChecker(BaseChecker):
       __implements__ = IAstroidChecker

pylint/checkers/utils.py

@@ -60,18 +60,7 @@
 import re
 import string
 from functools import lru_cache, partial
-from typing import (
-    Any,
-    Callable,
-    Dict,
-    Iterable,
-    List,
-    Match,
-    Optional,
-    Set,
-    Tuple,
-    Union,
-)
+from typing import Callable, Dict, Iterable, List, Match, Optional, Set, Tuple, Union
 
 import _string
 import astroid
@@ -1245,15 +1234,15 @@ def is_none(node: nodes.NodeNG) -> bool:
     )
 
 
-def node_type(node: nodes.NodeNG) -> Optional[Any]:
+def node_type(node: nodes.NodeNG) -> Optional[nodes.NodeNG]:
     """Return the inferred type for `node`
 
     If there is more than one possible type, or if inferred type is Uninferable or None,
     return None
     """
     # check there is only one possible type for the assign node. Else we
     # don't handle it for now
-    types = set()
+    types: Set[nodes.NodeNG] = set()
     try:
         for var_type in node.infer():
             if var_type == astroid.Uninferable or is_none(var_type):

pylint/pyreverse/inspector.py

@@ -152,16 +152,6 @@ def visit_project(self, node: Project) -> None:
         for module in node.modules:
             self.visit(module)
 
-    def visit_package(self, node) -> None:
-        """visit an astroid.Package node
-
-        * optionally tag the node with a unique id
-        """
-        if self.tag:
-            node.uid = self.generate_id()
-        for subelmt in node.values():
-            self.visit(subelmt)
-
     def visit_module(self, node: nodes.Module) -> None:
         """visit an astroid.Module node