diff --git a/skydoc/build.proto b/skydoc/build.proto
index 0a7fe44..6575eaa 100644
--- a/skydoc/build.proto
+++ b/skydoc/build.proto
@@ -16,6 +16,8 @@ syntax = "proto2";
 
 package skydoc;
 
+option py_api_version = 2;
+
 message Attribute {
   // Indicates the type of attribute.
   enum Discriminator {
diff --git a/skydoc/common_test.py b/skydoc/common_test.py
index 8e8e25d..9d8cd9d 100644
--- a/skydoc/common_test.py
+++ b/skydoc/common_test.py
@@ -14,6 +14,7 @@
 
 import unittest
 
+
 from skydoc import common
 
 
diff --git a/skydoc/macro_extractor.py b/skydoc/macro_extractor.py
index 4269d42..08f2743 100644
--- a/skydoc/macro_extractor.py
+++ b/skydoc/macro_extractor.py
@@ -19,6 +19,7 @@
 from skydoc import build_pb2
 from skydoc import common
 
+
 def get_type(expr):
   """Find the type of an expression.
 
diff --git a/skydoc/macro_extractor_test.py b/skydoc/macro_extractor_test.py
index 79b3d95..bee9e89 100644
--- a/skydoc/macro_extractor_test.py
+++ b/skydoc/macro_extractor_test.py
@@ -13,6 +13,7 @@
 # limitations under the License.
 
 
+
 import os
 import tempfile
 import textwrap
diff --git a/skydoc/main.py b/skydoc/main.py
index bce2e64..511bded 100755
--- a/skydoc/main.py
+++ b/skydoc/main.py
@@ -14,6 +14,7 @@
 
 """Documentation generator for Skylark"""
 
+
 import gflags
 import jinja2
 import os
@@ -46,8 +47,10 @@
 DEFAULT_OUTPUT_DIR = '.'
 DEFAULT_OUTPUT_FILE = 'skydoc.zip'
 
+WORKSPACE_DIR = 'io_bazel_skydoc'
 TEMPLATE_PATH = 'skydoc/templates'
 CSS_PATH = 'skydoc/sass'
+
 CSS_FILE = 'main.css'
 CSS_DIR = 'css'
 
@@ -87,7 +90,7 @@ def _runfile_path(path):
       break
 
     raise AssertionError('Cannot find .runfiles directory.')
-  return os.path.join(runfiles_dir, 'io_bazel_skydoc', path)
+  return os.path.join(runfiles_dir, WORKSPACE_DIR, path)
 
 def merge_languages(macro_language, rule_language):
   for rule in rule_language.rule:
diff --git a/skydoc/rule.py b/skydoc/rule.py
index 5ac2114..b7b7657 100644
--- a/skydoc/rule.py
+++ b/skydoc/rule.py
@@ -14,6 +14,7 @@
 
 """Representations used for rendering documentation templates."""
 
+
 import mistune
 from skydoc import build_pb2
 
diff --git a/skydoc/rule_extractor.py b/skydoc/rule_extractor.py
index 65c6600..776ee8f 100644
--- a/skydoc/rule_extractor.py
+++ b/skydoc/rule_extractor.py
@@ -16,11 +16,13 @@
 
 import ast
 
+
 from skydoc import build_pb2
 from skydoc import common
 from skydoc.stubs import attr
 from skydoc.stubs import skylark_globals
 
+
 SKYLARK_STUBS = {
     "attr": attr,
     "aspect": skylark_globals.aspect,
@@ -38,6 +40,7 @@
 }
 """Stubs for Skylark globals to be used to evaluate the .bzl file."""
 
+
 class RuleDocExtractor(object):
   """Extracts documentation for rules from a .bzl file."""
 
diff --git a/skydoc/rule_extractor_test.py b/skydoc/rule_extractor_test.py
index 6264509..b8a093b 100644
--- a/skydoc/rule_extractor_test.py
+++ b/skydoc/rule_extractor_test.py
@@ -12,11 +12,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import unittest
+
 
 import os
 import tempfile
 import textwrap
+import unittest
 from google.protobuf import text_format
 from skydoc import build_pb2
 from skydoc import rule_extractor
diff --git a/skydoc/stubs/attr.py b/skydoc/stubs/attr.py
index faa49ad..3912d97 100644
--- a/skydoc/stubs/attr.py
+++ b/skydoc/stubs/attr.py
@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+
 from skydoc import build_pb2
 
 def strcmp(s1, s2):
diff --git a/skylark/skylark.bzl b/skylark/skylark.bzl
index 92225f6..93d1079 100644
--- a/skylark/skylark.bzl
+++ b/skylark/skylark.bzl
@@ -39,7 +39,7 @@ def _skylark_library_impl(ctx):
                 transitive_bzl_files = sources)
 
 def _skydoc(ctx):
-  for f in ctx.files._skydoc:
+  for f in ctx.files.skydoc:
     if not f.path.endswith(".py"):
       return f
 
@@ -151,7 +151,7 @@ Example:
 
 _skylark_doc_attrs = {
     "format": attr.string(default = "markdown"),
-    "_skydoc": attr.label(
+    "skydoc": attr.label(
         default = Label("//skydoc"),
         cfg = HOST_CFG,
         executable = True),