Explain a bit more about navigate.

product/ERP5SecurePayment/interfaces/payment_service.py

@@ -44,7 +44,11 @@ class IPaymentService(Interface):
     """
     
   def navigate(self, REQUEST=None, **kw):
-    """Redirect User to the payment page.
+    """Redirects User to the payment page.
+
+    Implementation shall prepare service's expected HTTP query and return
+    correct HTTP response to browser which will lead to external payment page
+    with all required parameters.
     """
     
   def reportPaymentStatus(self, REQUEST=None):
@@ -60,4 +64,4 @@ class IPaymentService(Interface):
     
   def notifyCancel(self, REQUEST=None, **kw):
     """Fallback method when transaction is cancelled
-    """
+    """
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