Move the iter_errors and normalizer methods to grammar.py.

test/test_file_python_errors.py

@@ -19,5 +19,5 @@ def test_on_itself(each_version):
     path = os.path.dirname(os.path.dirname(__file__)) + '/parso'
     for file in get_python_files(path):
         tree = grammar.parse(path=file)
-        errors = list(tree._iter_errors(grammar))
+        errors = list(grammar.iter_errors(tree))
         assert not errors

test/test_normalizer_issues_files.py

@@ -60,7 +60,7 @@ def test_normalizer_issue(normalizer_issue_case):
 
     grammar = parso.load_grammar(version=normalizer_issue_case.python_version)
     module = grammar.parse(code)
-    issues = module._get_normalizer_issues(grammar)
+    issues = grammar._get_normalizer_issues(module)
     actual = sort(issues)
 
     diff = '\n'.join(difflib.ndiff(desired, actual))

test/test_pep8.py

@@ -4,7 +4,7 @@ import parso
 def issues(code):
     grammar = parso.load_grammar()
     module = parso.parse(code)
-    return module._get_normalizer_issues(grammar)
+    return grammar._get_normalizer_issues(module)
 
 
 def test_eof_newline():

test/test_python_errors.py

@@ -13,7 +13,7 @@ from .failing_examples import FAILING_EXAMPLES, indent, build_nested
 def _get_error_list(code, version=None):
     grammar = parso.load_grammar(version=version)
     tree = grammar.parse(code)
-    return list(tree._iter_errors(grammar))
+    return list(grammar.iter_errors(tree))
 
 def assert_comparison(code, error_code, positions):
     errors = [(error.start_pos, error.code) for error in _get_error_list(code)]