Remove six and cloudpickle from setup.py. (#7694)

python/ray/utils.py

@@ -5,7 +5,6 @@ import inspect
 import logging
 import numpy as np
 import os
-import six
 import subprocess
 import sys
 import tempfile
@@ -223,32 +222,14 @@ def decode(byte_str, allow_none=False):
 def ensure_str(s, encoding="utf-8", errors="strict"):
     """Coerce *s* to `str`.
 
-    To keep six with lower version, see Issue 4169, we copy this function
-    from six == 1.12.0.
-
-    TODO(yuhguo): remove this function when six >= 1.12.0.
-
-    For Python 2:
-      - `unicode` -> encoded to `str`
-      - `str` -> `str`
-
-    For Python 3:
       - `str` -> `str`
       - `bytes` -> decoded to `str`
     """
-    if six.PY3:
-        text_type = str
-        binary_type = bytes
+    if isinstance(s, str):
+        return s
     else:
-        text_type = unicode  # noqa: F821
-        binary_type = str
-    if not isinstance(s, (text_type, binary_type)):
-        raise TypeError("not expecting type '%s'" % type(s))
-    if six.PY2 and isinstance(s, text_type):
-        s = s.encode(encoding, errors)
-    elif six.PY3 and isinstance(s, binary_type):
-        s = s.decode(encoding, errors)
-    return s
+        assert isinstance(s, bytes)
+        return s.decode(encoding, errors)
 
 
 def binary_to_object_id(binary_object_id):