diff --git a/parso/grammar.py b/parso/grammar.py
index f1e4958..3609278 100644
--- a/parso/grammar.py
+++ b/parso/grammar.py
@@ -21,7 +21,7 @@ class Grammar(object):
 
     :param text: A BNF representation of your grammar.
     """
-    _error_finder_config = None
+    _error_normalizer_config = None
     _default_normalizer_config = pep8.PEP8NormalizerConfig()
 
     def __init__(self, text, tokenizer, parser=BaseParser, diff_parser=None):
@@ -161,7 +161,6 @@ class Grammar(object):
 
 class PythonGrammar(Grammar):
     _error_normalizer_config = ErrorFinderConfig()
-    _parser_cls = PythonParser
 
     def __init__(self, version_info, bnf_text):
         super(PythonGrammar, self).__init__(
diff --git a/parso/python/normalizer.py b/parso/python/normalizer.py
index b128be2..e852795 100644
--- a/parso/python/normalizer.py
+++ b/parso/python/normalizer.py
@@ -127,7 +127,7 @@ def _get_for_stmt_definition_exprs(for_stmt):
     return list(_iter_definition_exprs_from_lists(exprlist))
 
 
-class Context(object):
+class _Context(object):
     def __init__(self, node, add_syntax_error, parent_context=None):
         self.node = node
         self.blocks = []
@@ -245,7 +245,7 @@ class Context(object):
         self.blocks.pop()
 
     def add_context(self, node):
-        return Context(node, self._add_syntax_error, parent_context=self)
+        return _Context(node, self._add_syntax_error, parent_context=self)
 
     def close_child_context(self, child_context):
         self._nonlocal_names_in_subscopes += child_context.finalize()
@@ -266,7 +266,7 @@ class ErrorFinder(Normalizer):
             parent_scope = node
         else:
             parent_scope = search_ancestor(node, allowed)
-        self._context = Context(parent_scope, self._add_syntax_error)
+        self._context = _Context(parent_scope, self._add_syntax_error)
         self._indentation_count = 0
 
     def visit(self, node):