Start working with mypy

parso/cache.py

@@ -7,11 +7,7 @@ import shutil
 import platform
 import logging
 import warnings
-
-try:
-    import cPickle as pickle
-except:
-    import pickle
+import pickle
 
 from parso.file_io import FileIO
 

parso/normalizer.py

@@ -149,8 +149,8 @@ class Issue(object):
 
 
 class Rule(object):
-    code = None
-    message = None
+    code: int
+    message: str
 
     def __init__(self, normalizer):
         self._normalizer = normalizer

parso/tree.py

@@ -23,7 +23,7 @@ class NodeOrLeaf(object):
     The base class for nodes and leaves.
     """
     __slots__ = ()
-    type = None
+    type: str
     '''
     The type is a string that typically matches the types of the grammar file.
     '''
@@ -257,7 +257,6 @@ class BaseNode(NodeOrLeaf):
     A node has children, a type and possibly a parent node.
     """
     __slots__ = ('children', 'parent')
-    type = None
 
     def __init__(self, children):
         self.children = children