diff --git a/python/licenseck.py b/python/licenseck.py
index 0e862e35ef4..0b2f6700c82 100644
--- a/python/licenseck.py
+++ b/python/licenseck.py
@@ -7,25 +7,29 @@
 # option. This file may not be copied, modified, or distributed
 # except according to those terms.
 
-license0="""\
+
+# These licenses are valid for use in Servo
+licenses = [
+
+"""\
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-"""
+""",
 
-license1="""\
+"""\
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
-"""
+""",
 
-license2="""\
+"""\
 // This Source Code Form is subject to the terms of the Mozilla Public
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
-"""
+""",
 
-license3 = """\
+"""\
 // Copyright 2013 The Servo Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution.
 //
@@ -34,9 +38,9 @@ license3 = """\
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
-"""
+""",
 
-license4 = """\
+"""\
 # Copyright 2013 The Servo Project Developers. See the COPYRIGHT
 # file at the top-level directory of this distribution.
 #
@@ -45,31 +49,6 @@ license4 = """\
 # <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 # option. This file may not be copied, modified, or distributed
 # except according to those terms.
-"""
+""",
 
-licenses = [license0, license1, license2, license3, license4]
-
-exceptions = [
-    "servo/dom/bindings/codegen/ply/ply/yacc.py", # BSD
-    "servo/dom/bindings/codegen/ply/ply/__init__.py", # BSD
-    "servo/dom/bindings/codegen/ply/ply/lex.py", # BSD
 ]
-
-def check_license(name, contents):
-    valid_license = False
-    for a_valid_license in licenses:
-        if contents.startswith(a_valid_license):
-            valid_license = True
-            break
-    if valid_license:
-        return True
-
-    for exception in exceptions:
-        if name.endswith(exception):
-            return True
-
-    firstlineish = contents[:100]
-    if firstlineish.find("xfail-license") != -1:
-        return True
-
-    return False
diff --git a/python/tidy.py b/python/tidy.py
index dd4ba848213..ee1372761fa 100644
--- a/python/tidy.py
+++ b/python/tidy.py
@@ -11,7 +11,7 @@
 
 import os
 import fnmatch
-import licenseck
+from licenseck import licenses
 
 directories_to_check = ["src", "components"]
 filetypes_to_check = [".rs", ".rc", ".cpp", ".c", ".h", ".py"]
@@ -45,12 +45,14 @@ def should_check(file_name):
     return True
 
 
-def check_license(file_name, contents):
-    if not licenseck.check_license(file_name, contents):
+def check_license(contents):
+    valid_license = any(contents.startswith(license) for license in licenses)
+    acknowledged_bad_license = "xfail-license" in contents[:100]
+    if not (valid_license or acknowledged_bad_license):
         yield (1, "incorrect license")
 
 
-def check_whitespace(file_name, contents):
+def check_whitespace(contents):
     lines = contents.splitlines(True)
     for idx, line in enumerate(lines):
         if line[-1] == "\n":
@@ -73,7 +75,7 @@ def collect_errors_for_files(files_to_check, checking_functions):
         with open(file_name, "r") as fp:
             contents = fp.read()
             for check in checking_functions:
-                for error in check(file_name, contents):
+                for error in check(contents):
                     # filename, line, message
                     yield (file_name, error[0], error[1])