--- a/testing/mozharness/scripts/awsy_script.py
+++ b/testing/mozharness/scripts/awsy_script.py
@@ -167,17 +167,17 @@ class AWSY(TestingMixin, MercurialScript
             # Allow the child process to import dmd.py
             python_path = os.environ.get('PYTHONPATH')
 
             if python_path:
                 os.environ['PYTHONPATH'] = "%s%s%s" % (python_path, os.pathsep, dmd_py_lib_dir)
             else:
                 os.environ['PYTHONPATH'] = dmd_py_lib_dir
 
-            env['DMD']= "--mode=dark-matter --stacks=full"
+            env['DMD'] = "--mode=dark-matter --stacks=full"
 
         runtime_testvars_path = os.path.join(self.awsy_path, 'runtime-testvars.json')
         runtime_testvars_file = open(runtime_testvars_path, 'wb')
         runtime_testvars_file.write(json.dumps(runtime_testvars, indent=2))
         runtime_testvars_file.close()
 
         cmd = ['marionette']