In this first example, when a call is directed to this example XML document, the caller will hear “Go Green, Go Plivo” spoken once. Example Request 
from plivo import plivoxml

response = (plivoxml.ResponseElement()
            .add(plivoxml.SpeakElement('Go Green, Go Plivo.')))
print(response.to_string())
Response 
<Response>
    <Speak>Go Green, Go Plivo.</Speak>
</Response>