'Validate a request from Twilio
:param uri: full URI that Twilio requested on your server
:param params: post vars that Twilio sent with the request
:param signature: expected signature in HTTP X-Twilio-Signature header
:returns: True if the request passes validation, False if not'

def validate(self, uri, params, signature):

    return compare(self.compute_signature(uri, params), signature)
