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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def require_oauth(self, realm=None, require_resource_owner=True, require_verifier=False, require_realm=False):
 """Mark the view function f as a protected resource"""


        def decorator(f):
            @wraps(f)
            def verify_request(*args, **kwargs):
                """Verify OAuth params before running view function f"""
                try:
                    if request.form:
                        body = request.form.to_dict()
                    else:
                        body = request.data.decode("utf-8")
                    verify_result = self.verify_request(request.url.decode("utf-8"),
                            http_method=request.method.decode("utf-8"),
                            body=body,
                            headers=request.headers,
                            require_resource_owner=require_resource_owner,
                            require_verifier=require_verifier,
                            require_realm=require_realm or bool(realm),
                            required_realm=realm)
                    valid, oauth_request = verify_result
                    if valid:
                        request.oauth = self.collect_request_parameters(request)

                        # Request tokens are only valid when a verifier is too
                        token = {}
                        if require_verifier:
                            token[u'request_token'] = request.oauth.resource_owner_key
                        else:
                            token[u'access_token'] = request.oauth.resource_owner_key

                        # All nonce/timestamp pairs must be stored to prevent
                        # replay attacks, they may be connected to a specific
                        # client and token to decrease collision probability.
                        self.save_timestamp_and_nonce(request.oauth.client_key,
                                request.oauth.timestamp, request.oauth.nonce,
                                **token)

                        # By this point, the request is fully authorized
                        return f(*args, **kwargs)
                    else:
                        # Unauthorized requests should not diclose their cause
                        raise Unauthorized()

                except ValueError as err:
                    # Caused by missing of or badly formatted parameters
                    raise BadRequest(err.message)

            return verify_request
        return decorator