diff --git a/arcanist/linter/PythonFileEncodingLinter.php b/arcanist/linter/PythonFileEncodingLinter.php
index a193d8d4e..93c6697df 100644
--- a/arcanist/linter/PythonFileEncodingLinter.php
+++ b/arcanist/linter/PythonFileEncodingLinter.php
@@ -1,93 +1,93 @@
 <?php
 
 /**
  * Make sure we explicitly set the encoding when opening text files with
  * Python.
  */
 final class PythonFileEncodingLinter extends ArcanistLinter {
 
   const ENCODING_NOT_FOUND = 1;
 
   public function getInfoName() {
     return 'lint-python-encoding';
   }
 
   public function getInfoDescription() {
     return pht('Make sure we explicitly set the encoding when reading text '.
                'content with Python');
   }
 
   public function getLinterName() {
     return 'PYTHON_ENCODING';
   }
 
   public function getLinterConfigurationName() {
     return 'lint-python-encoding';
   }
 
   public function getLintSeverityMap() {
     return array(
       self::ENCODING_NOT_FOUND => ArcanistLintSeverity::SEVERITY_ERROR,
     );
   }
 
   public function getLintNameMap() {
     return array(
       self::ENCODING_NOT_FOUND => pht('Encoding should be specified when '.
                                       'reading text content.'),
     );
   }
 
   public function lintPath($path) {
     $path = Filesystem::resolvePath($path, $this->getProjectRoot());
     $fileContent = Filesystem::readFile($path);
 
     $pattern = "/[(\s]open(\(((?>[^()]+)|(?1))*\))/";
     if (preg_match_all($pattern, $fileContent, $matches,
       PREG_OFFSET_CAPTURE)) {
       foreach ($matches[0] as $match) {
         list($open, $offset) = $match;
 
         $isBin = preg_match(
-          "/open\(.*, ['\"][rwxat+]*b[rwxat+]*['\"]/", $open);
+          "/open\(.*,\s? +['\"][rwxat+]*b[rwxat+]*['\"]/s", $open);
         $hasEncoding = preg_match("/encoding=.(ascii|utf8|utf-8)./", $open);
 
         if (!$isBin && !$hasEncoding) {
           $this->raiseLintAtOffset(
             $offset + 1,
             self::ENCODING_NOT_FOUND,
             pht("Python's open(...) seems to be used to open text files ".
                 "without explicitly specifying encoding, or with an invalid ".
                 "encoding. Encoding should be 'ascii', 'utf-8' or 'utf8' ".
                 "(e.g.: `open(f, 'r', encoding='utf-8')`)."),
             substr($open, 1),
             null);
         }
       }
     }
 
     $pattern = "/[(\s]check_output(\(((?>[^()]+)|(?1))*\))/";
     if (preg_match_all($pattern, $fileContent, $matches,
       PREG_OFFSET_CAPTURE)) {
       foreach ($matches[0] as $match) {
         list($check_output, $offset) = $match;
 
         $isText = preg_match("/universal_newlines=True/", $check_output);
         $hasEncoding = preg_match("/encoding=.(ascii|utf8|utf-8)./",
           $check_output);
 
         if ($isText && !$hasEncoding) {
           $this->raiseLintAtOffset(
               $offset + 1,
               self::ENCODING_NOT_FOUND,
               pht("Python's check_output(...) seems to be used to get program ".
                   "output without explicitly specifying encoding, or with an ".
                   "invalid encoding. Encoding should be 'ascii', 'utf-8' or ".
                   "'utf8'"),
               substr($check_output, 1),
               null);
         }
       }
     }
   }
 }