diff --git a/scrapy/utils/url.py b/scrapy/utils/url.py
index bc8236e1a..dd7ca85ab 100644
--- a/scrapy/utils/url.py
+++ b/scrapy/utils/url.py
@@ -5,7 +5,6 @@ library.
 Some of the functions that used to be imported from this module have been moved
 to the w3lib.url module. Always import those from there instead.
 """
-
 import urlparse
 import urllib
 import cgi
@@ -13,6 +12,7 @@ import cgi
 from w3lib.url import *
 from scrapy.utils.python import unicode_to_str
 
+
 def url_is_from_any_domain(url, domains):
     """Return True if the url belongs to any of the given domains"""
     host = parse_url(url).netloc
@@ -22,15 +22,18 @@ def url_is_from_any_domain(url, domains):
     else:
         return False
 
+
 def url_is_from_spider(url, spider):
     """Return True if the url belongs to the given spider"""
-    return url_is_from_any_domain(url, [spider.name] + \
-        getattr(spider, 'allowed_domains', []))
+    return url_is_from_any_domain(url,
+        [spider.name] + list(getattr(spider, 'allowed_domains', [])))
+
 
 def url_has_any_extension(url, extensions):
     return posixpath.splitext(parse_url(url).path)[1].lower() in extensions
 
-def canonicalize_url(url, keep_blank_values=True, keep_fragments=False, \
+
+def canonicalize_url(url, keep_blank_values=True, keep_fragments=False,
         encoding=None):
     """Canonicalize the given url by applying the following procedures:
 
@@ -70,6 +73,7 @@ def parse_url(url, encoding=None):
     return url if isinstance(url, urlparse.ParseResult) else \
         urlparse.urlparse(unicode_to_str(url, encoding))
 
+
 def escape_ajax(url):
     """
     Return the crawleable url according to: