Get rid of some Python 2 idiosyncrasies

docs/docs/development.rst

@@ -29,10 +29,10 @@ To run the tests for all supported Python versions::
 
     tox
 
-If you want to test only a specific Python version (e.g. Python 2.7), it's as
+If you want to test only a specific Python version (e.g. Python 3.9), it's as
 easy as::
 
-    tox -e py27
+    tox -e py39
 
 Tests are also run automatically on `Travis CI
 <https://travis-ci.org/davidhalter/parso/>`_.

parso/cache.py

@@ -140,17 +140,10 @@ def load_module(hashed_grammar, file_io, cache_path=None):
 
 def _load_from_file_system(hashed_grammar, path, p_time, cache_path=None):
     cache_path = _get_hashed_path(hashed_grammar, path, cache_path=cache_path)
-    try:
     try:
         if p_time > os.path.getmtime(cache_path):
             # Cache is outdated
             return None
-        except OSError as e:
-            if e.errno == errno.ENOENT:
-                # In Python 2 instead of an IOError here we get an OSError.
-                raise FileNotFoundError
-            else:
-                raise
 
         with open(cache_path, 'rb') as f:
             gc.disable()

parso/python/tokenize.py

@@ -48,21 +48,8 @@ BOM_UTF8_STRING = BOM_UTF8.decode('utf-8')
 
 _token_collection_cache = {}
 
-if sys.version_info.major >= 3:
-    # Python 3 has str.isidentifier() to check if a char is a valid identifier
-    is_identifier = str.isidentifier
-else:
-    # Python 2 doesn't, but it's not that important anymore and if you tokenize
-    # Python 2 code with this, it's still ok. It's just that parsing Python 3
-    # code with this function is not 100% correct.
-    # This just means that Python 2 code matches a few identifiers too much,
-    # but that doesn't really matter.
-    def is_identifier(s):
-        return True
 
-
-def group(*choices, **kwargs):
-    capture = kwargs.pop('capture', False)  # Python 2, arrghhhhh :(
+def group(*choices, capture=False, **kwargs):
     assert not kwargs
 
     start = '('
@@ -555,7 +542,7 @@ def tokenize_lines(lines, version_info, start_pos=(1, 0), indents=None, is_first
                     m = re.match(r'[ \f\t]*$', line[:start])
                     if m is not None:
                         yield from dedent_if_necessary(m.end())
-                if is_identifier(token):
+                if token.is_identifier():
                     yield PythonToken(NAME, token, spos, prefix)
                 else:
                     yield from _split_illegal_unicode_name(token, spos, prefix)

parso/python/tree.py

@@ -310,10 +310,6 @@ class _StringComparisonMixin(object):
 
         return self is other
 
-    def __ne__(self, other):
-        """Python 2 compatibility."""
-        return not self.__eq__(other)
-
     def __hash__(self):
         return hash(self.value)