remove python 2 compatibility code

Author: ARF1

llvmlite/binding/value.py

@@ -1,9 +1,8 @@
 from ctypes import POINTER, c_char_p, c_int, c_size_t, c_uint, c_uint64, c_bool, c_void_p
 import enum
 
-from . import ffi
-from .common import _decode_string, _encode_string
-from .. import six
+from llvmlite.binding import ffi
+from llvmlite.binding.common import _decode_string, _encode_string
 
 
 class Linkage(enum.IntEnum):
@@ -202,7 +201,7 @@ def add_function_attribute(self, attr, val=None):
             # if attribute is not an EnumAttribute, add it as a StringAttribute
             val = 'true' if val is True or val is None else val
             val = 'false' if val is False else val
-            if not isinstance(val, six.string_types):
+            if not isinstance(val, str):
                 raise ValueError(
                     "attribute '%s' takes only string or boolean values, got '%s'" % (attrname, type(val)))
             ffi.lib.LLVMPY_AddFunctionStringAttr(

llvmlite/tests/test_binding.py

@@ -859,14 +859,9 @@ def test_add_function_attribute(self):
             "attribute 'nocapture' only takes 'None' as value")
         with self.assertRaises(ValueError) as raises:
             fn.add_function_attribute("no-nans-fp-math", 1)
-        if six.PY2:
-            self.assertEqual(
-                str(raises.exception), 
-                "attribute 'no-nans-fp-math' takes only string or boolean values, got '<type 'int'>'")
-        else:
-            self.assertEqual(
-                str(raises.exception), 
-                "attribute 'no-nans-fp-math' takes only string or boolean values, got '<class 'int'>'")
+        self.assertEqual(
+            str(raises.exception), 
+            "attribute 'no-nans-fp-math' takes only string or boolean values, got '<class 'int'>'")
 
     def test_module(self):
         mod = self.module()