How to allow only GET and PATCH request using apigee?

Question

I am using apigee to allow only GET and PATCH request. I want to raise a fault for all other requests with error code 403. For that I have used Raised Fault policy.

    <PreFlow name="PreFlow">
       <Request>
           <Step>
              <Name>RF-only-GET-PATCH</Name>
                <Condition>(request.verb !="GET") || (request.verb !="PATCH")</Condition>
                </Step>
               </Request>
            <Response/>
        </PreFlow>

    Also tried following combinations :

     <Condition>(request.verb !="GET") || (request.verb !="PATCH")</Condition>
     <Condition>(request.verb !="GET") or (request.verb !="PATCH")</Condition>
     <Condition>((request.verb !="GET") || (request.verb !="PATCH"))</Condition>

this is not worked.

What should be the condition to raise the fault : RF-only-GET-PATCH ?