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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 parse_authn_request_response(self, xmlstr, binding, outstanding=None, outstanding_certs=None, conv_info=None):
 """ Deal with an AuthnResponse :param xmlstr: The reply as a xml string :param binding: Which binding that was used for the transport :param outstanding: A dictionary with session IDs as keys and the original web request from the user before redirection as values. :param outstanding_certs: :param conv_info: Information about the conversation. :return: An response.AuthnResponse or None """


        if not getattr(self.config, 'entityid', None):
            raise SAMLError("Missing entity_id specification")

        if not xmlstr:
            return None

        kwargs = {
            "outstanding_queries": outstanding,
            "outstanding_certs": outstanding_certs,
            "allow_unsolicited": self.allow_unsolicited,
            "want_assertions_signed": self.want_assertions_signed,
            "want_assertions_or_response_signed": self.want_assertions_or_response_signed,
            "want_response_signed": self.want_response_signed,
            "return_addrs": self.service_urls(binding=binding),
            "entity_id": self.config.entityid,
            "attribute_converters": self.config.attribute_converters,
            "allow_unknown_attributes":
                self.config.allow_unknown_attributes,
            'conv_info': conv_info
        }

        try:
            resp = self._parse_response(xmlstr, AuthnResponse,
                                        "assertion_consumer_service",
                                        binding, **kwargs)
        except StatusError as err:
            logger.error("SAML status error: %s", err)
            raise
        except UnravelError:
            return None
        except Exception as err:
            logger.error("XML parse error: %s", err)
            raise

        if not isinstance(resp, AuthnResponse):
            logger.error("Response type not supported: %s",
                         saml2.class_name(resp))
            return None

        if (resp.assertion and len(resp.response.encrypted_assertion) == 0 and
                resp.assertion.subject.name_id):
            self.users.add_information_about_person(resp.session_info())
            logger.info("--- ADDED person info ----")

        return resp