many pep8 improvements

gluon/contrib/google_wallet.py

@@ -1,5 +1,6 @@
 from gluon import XML
 
+
 def button(merchant_id="123456789012345",
            products=[dict(name="shoes",
                           quantity=1,
@@ -8,8 +9,8 @@ def button(merchant_id="123456789012345",
                           description="running shoes black")]):
     t = '<input name="item_%(key)s_%(k)s" type="hidden" value="%(value)s"/>'
     list_products = ''
-    for k,product in enumerate(products):
-        for key,value in product.items():
-            list_products += t % dict(k=k+1,key=key,value=value)
+    for k, product in enumerate(products):
+        for key, value in product.items():
+            list_products += t % dict(k=k + 1, key=key, value=value)
     button = '<form action="https://checkout.google.com/api/checkout/v2/checkoutForm/Merchant/%s" id="BB_BuyButtonForm" method="post" name="BB_BuyButtonForm" target="_top">%s<input name="_charset_" type="hidden" value="utf-8"/><input alt="" src="https://checkout.google.com/buttons/buy.gif?merchant_id=%s&amp;w=117&amp;h=48&amp;style=white&amp;variant=text&amp;loc=en_US" type="image"/></form>' % (merchant_id, list_products, merchant_id)
     return XML(button)