fix pep8 E731

(do not assign a lambda, use a def)

base_partner_merge/base_partner_merge.py

@@ -388,7 +388,8 @@ class MergePartnerAutomatic(orm.TransientModel):
                   " merge several contacts linked to existing Journal "
                   "Items."))
 
-        call_it = lambda function: function(cr, uid, src_partners,
+        def call_it(function):
+            function(cr, uid, src_partners,
                      dst_partner, context=context)
 
         call_it(self._update_foreign_keys)