diff --git a/book_tools/format/__init__.py b/book_tools/format/__init__.py
index 761edb02880adefe7afadbb82f59fedc758dacaf..ce8a191a371827c935f5cb781a40c83e9c5793f2 100644
--- a/book_tools/format/__init__.py
+++ b/book_tools/format/__init__.py
@@ -15,9 +15,9 @@ from book_tools.format.mobi import Mobipocket
 
 from constance import config
 
-class __detector:
+class mime_detector:
     @staticmethod
-    def format(fmt):
+    def fmt(fmt):
         if fmt.lower() == 'xml':
             return Mimetype.XML
         elif fmt.lower() == 'fb2':
@@ -44,11 +44,11 @@ class __detector:
     @staticmethod
     def file(filename):
         (n, e) = os.path.splitext(filename)
-        return format(e[1:])
+        return mime_detector.fmt(e[1:])
 
 def detect_mime(file, original_filename):
     FB2_ROOT = 'FictionBook'
-    mime = __detector.file(original_filename)
+    mime = mime_detector.file(original_filename)
 
     try:
         if mime == Mimetype.XML:
diff --git a/opds_catalog/dl.py b/opds_catalog/dl.py
index 918683f5cc50ac8512c4cba8cf57f31721e91264..8d6e01319ae44b1573c9aaf818de01a163d4ba02 100644
--- a/opds_catalog/dl.py
+++ b/opds_catalog/dl.py
@@ -12,7 +12,7 @@ from opds_catalog.models import Book, bookshelf
 from opds_catalog import settings, utils, opdsdb, fb2parse
 import opds_catalog.zipf as zipfile
 
-from book_tools.format import create_bookfile, __detector
+from book_tools.format import create_bookfile, mime_detector
 from book_tools.format.mimetype import Mimetype
 
 from constance import config
@@ -45,7 +45,7 @@ def Download(request, book_id, zip_flag):
         content_type= Mimetype.FB2_ZIP if book.format=='fb2' else Mimetype.ZIP
     else:    
         dlfilename=transname
-        content_type = __detector.format(book.format)
+        content_type = mime_detector.fmt(book.format)
 
     response = HttpResponse()
     response["Content-Type"]='%s; name="%s"'%(content_type,dlfilename)
@@ -240,7 +240,7 @@ def ConvertFB2(request, book_id, convert_type):
         converter_path=config.SOPDS_FB2TOEPUB
     elif convert_type=='mobi':
         converter_path=config.SOPDS_FB2TOMOBI
-    content_type=__detector.format(convert_type)
+    content_type=mime_detector.fmt(convert_type)
 
     if book.cat_type==opdsdb.CAT_NORMAL:
         tmp_fb2_path=None
diff --git a/opds_catalog/feeds.py b/opds_catalog/feeds.py
index 2c89dba5e7ea85a5e14a18e390c868feb305583a..d0c27fe38645220a1078a26b98a56a25d6688895 100644
--- a/opds_catalog/feeds.py
+++ b/opds_catalog/feeds.py
@@ -12,7 +12,7 @@ from opds_catalog import settings
 from opds_catalog.middleware import BasicAuthMiddleware
 from opds_catalog.opds_paginator import Paginator as OPDS_Paginator
 
-from book_tools.format import __detector as detector
+from book_tools.format import mime_detector
 from book_tools.format.mimetype import Mimetype
 
 from constance import config
@@ -294,7 +294,7 @@ class CatalogsFeed(AuthFeed):
         if item['is_catalog']:
             return (opdsEnclosure(reverse("opds_catalog:cat_tree", kwargs={"cat_id":item['id']}),"application/atom+xml;profile=opds-catalog;kind=navigation", "subsection"),)
         else:
-            mime = detector.format(item['format'])
+            mime = mime_detector.fmt(item['format'])
             enclosure = [opdsEnclosure(reverse("opds_catalog:download", kwargs={"book_id": item['id'], "zip_flag": 0}), mime, "http://opds-spec.org/acquisition/open-access"),]
             if not item['format'] in settings.NOZIP_FORMATS:
                 mimezip = Mimetype.FB2_ZIP if mime == Mimetype.FB2 else "%s+zip" % mime
@@ -541,7 +541,7 @@ class SearchBooksFeed(AuthFeed):
         return item['registerdate'] 
          
     def item_enclosures(self, item):
-        mime = detector.format(item['format'])
+        mime = mime_detector.fmt(item['format'])
         enclosure = [
             opdsEnclosure(reverse("opds_catalog:download", kwargs={"book_id": item['id'], "zip_flag": 0}), mime, "http://opds-spec.org/acquisition/open-access"), ]
         if not item['format'] in settings.NOZIP_FORMATS: