diff --git a/lib/blackboxprotobuf/lib/api.py b/lib/blackboxprotobuf/lib/api.py
index de9c6ec..8c41710 100644
--- a/lib/blackboxprotobuf/lib/api.py
+++ b/lib/blackboxprotobuf/lib/api.py
@@ -770,7 +770,7 @@ def _annotate_typedef(typedef, message):
         # Add a blank name field if the field doesn't have one, so it's easier
         # to add
         if "name" not in field_def:
-            field_def["name"] = six.u("")
+            field_def["name"] = u""
 
 
 def _strip_typedef_annotations(typedef):
diff --git a/lib/blackboxprotobuf/lib/protofile.py b/lib/blackboxprotobuf/lib/protofile.py
index 7d5e778..3a2e873 100644
--- a/lib/blackboxprotobuf/lib/protofile.py
+++ b/lib/blackboxprotobuf/lib/protofile.py
@@ -23,7 +23,6 @@
 # SOFTWARE.
 
 import io
-import re
 import logging
 import re
 import six
@@ -98,7 +97,7 @@
 
 def _print_message(message_name, typedef, output_file, depth=0):
     # type: (str, TypeDefDict, TextIO, int) -> None
-    indent = six.u("  ") * depth
+    indent = u"  " * depth
     if not NAME_REGEX.match(message_name):
         raise TypedefException("Message name: %s is not valid" % message_name)
 
@@ -106,9 +105,9 @@ def _print_message(message_name, typedef, output_file, depth=0):
     typedef = blackboxprotobuf.lib.api.sort_typedef(typedef)
 
     message_name = message_name.strip()
-    output_file.write(six.u("\n"))
+    output_file.write(u"\n")
     output_file.write(indent)
-    output_file.write(six.u("message %s {\n") % message_name)
+    output_file.write(u"message %s {\n" % message_name)
     for field_number, field_typedef in typedef.items():
         proto_type = None
         field_name = None
@@ -157,7 +156,7 @@ def _print_message(message_name, typedef, output_file, depth=0):
 
         output_file.write(indent)
         output_file.write(
-            six.u("  %s%s %s = %s%s;\n")
+            u"  %s%s %s = %s%s;\n"
             % (
                 "repeated " if is_repeated else "",
                 proto_type,
@@ -168,7 +167,7 @@ def _print_message(message_name, typedef, output_file, depth=0):
         )
 
     output_file.write(indent)
-    output_file.write(six.u("}\n\n"))
+    output_file.write(u"}\n\n")
 
 
 def export_proto(typedef_map, output_filename=None, output_file=None, package=None):
@@ -186,9 +185,9 @@ def export_proto(typedef_map, output_filename=None, output_file=None, package=No
         output_file = io.StringIO()
 
     # preamble
-    output_file.write(six.u('syntax = "proto3";\n\n'))
+    output_file.write(u'syntax = "proto3";\n\n')
     if package:
-        output_file.write(six.u("package %s;\n\n") % package)
+        output_file.write(u"package %s;\n\n" % package)
 
     for typedef_name, typedef in typedef_map.items():
         _print_message(typedef_name, typedef, output_file)
diff --git a/lib/tests/py_test/test_protobuf.py b/lib/tests/py_test/test_protobuf.py
index 0f48762..5f56526 100644
--- a/lib/tests/py_test/test_protobuf.py
+++ b/lib/tests/py_test/test_protobuf.py
@@ -46,21 +46,21 @@
     import Test_pb2
 
 testMessage_typedef = {
-    "1": {"type": "double", "name": six.u("testDouble")},
-    "2": {"type": "float", "name": six.u("testFloat")},
+    "1": {"type": "double", "name": u"testDouble"},
+    "2": {"type": "float", "name": u"testFloat"},
     # "4": {"type": "int", "name": "testInt32"},
-    "8": {"type": "int", "name": six.u("testInt64")},
+    "8": {"type": "int", "name": u"testInt64"},
     # "16": {"type": "uint", "name": "testUInt32"},
-    "32": {"type": "uint", "name": six.u("testUInt64")},
+    "32": {"type": "uint", "name": u"testUInt64"},
     # "64": {"type": "sint", "name": "testSInt32"},
-    "128": {"type": "sint", "name": six.u("testSInt64")},
-    "256": {"type": "fixed32", "name": six.u("testFixed32")},
-    "512": {"type": "fixed64", "name": six.u("testFixed64")},
-    "1024": {"type": "sfixed32", "name": six.u("testSFixed32")},
-    "2048": {"type": "sfixed64", "name": six.u("testSFixed64")},
+    "128": {"type": "sint", "name": u"testSInt64"},
+    "256": {"type": "fixed32", "name": u"testFixed32"},
+    "512": {"type": "fixed64", "name": u"testFixed64"},
+    "1024": {"type": "sfixed32", "name": u"testSFixed32"},
+    "2048": {"type": "sfixed64", "name": u"testSFixed64"},
     # "4096": {"type": "int", "name": "testBool"},
-    "8192": {"type": "string", "name": six.u("testString")},
-    "16384": {"type": "bytes", "name": six.u("testBytes")},
+    "8192": {"type": "string", "name": u"testString"},
+    "16384": {"type": "bytes", "name": u"testBytes"},
     # "32768": {"type": "message", "name": "testEmbed",
     #          "message_typedef": {
     #                "3": {"type": "double", "name": "embedDouble"},
@@ -114,7 +114,7 @@ def test_modify(x, modify_num):
     hypothesis.assume(modify_key in decoded)
 
     if isinstance(decoded[modify_key], six.text_type):
-        mod_func = lambda x: six.u("test")
+        mod_func = lambda x: u"test"
     elif isinstance(decoded[modify_key], bytes):
         mod_func = lambda x: b"test"
     elif isinstance(decoded[modify_key], six.integer_types):
@@ -222,7 +222,7 @@ def test_modify_json(x, modify_num):
     hypothesis.assume(modify_key in decoded)
 
     if isinstance(decoded[modify_key], six.text_type):
-        mod_func = lambda x: six.u("test")
+        mod_func = lambda x: u"test"
     elif isinstance(decoded[modify_key], bytes):
         mod_func = lambda x: b"test"
     elif isinstance(decoded[modify_key], six.integer_types):