diff --git a/lib/galaxy/util/streamball.py b/lib/galaxy/util/streamball.py
index 528b0f90120..2fbaca8c1e9 100644
--- a/lib/galaxy/util/streamball.py
+++ b/lib/galaxy/util/streamball.py
@@ -2,11 +2,13 @@
 A simple wrapper for writing tarballs as a stream.
 """
 import os
-import logging, tarfile
+import logging
+import tarfile
 from galaxy.exceptions import ObjectNotFound
 
 log = logging.getLogger( __name__ )
 
+
 class StreamBall( object ):
     def __init__( self, mode, members=None ):
         self.members = members
@@ -15,16 +17,19 @@ class StreamBall( object ):
         self.mode = mode
         self.wsgi_status = None
         self.wsgi_headeritems = None
+
     def add( self, file, relpath, check_file=False):
-        if check_file and len(file)>0:
+        if check_file and len(file) > 0:
             if not os.path.isfile(file):
                 raise ObjectNotFound
             else:
                 self.members[file] = relpath
         else:
             self.members[file] = relpath
+
     def stream( self, environ, start_response ):
         response_write = start_response( self.wsgi_status, self.wsgi_headeritems )
+
         class tarfileobj:
             def write( self, *args, **kwargs ):
                 response_write( *args, **kwargs )
@@ -34,10 +39,12 @@ class StreamBall( object ):
         tf.close()
         return []
 
+
 class ZipBall(object):
     def __init__(self, tmpf, tmpd):
         self._tmpf = tmpf
         self._tmpd = tmpd
+
     def stream(self, environ, start_response):
         response_write = start_response( self.wsgi_status, self.wsgi_headeritems )
         tmpfh = open( self._tmpf )