How to use the onelogin.saml2.utils.OneLogin_Saml2_Utils.b64encode function in onelogin

msg = self.__build_sign_query(data[saml_type],
                                      data.get('RelayState', None),
                                      sign_algorithm,
                                      saml_type)

        sign_algorithm_transform_map = {
            OneLogin_Saml2_Constants.DSA_SHA1: xmlsec.Transform.DSA_SHA1,
            OneLogin_Saml2_Constants.RSA_SHA1: xmlsec.Transform.RSA_SHA1,
            OneLogin_Saml2_Constants.RSA_SHA256: xmlsec.Transform.RSA_SHA256,
            OneLogin_Saml2_Constants.RSA_SHA384: xmlsec.Transform.RSA_SHA384,
            OneLogin_Saml2_Constants.RSA_SHA512: xmlsec.Transform.RSA_SHA512
        }
        sign_algorithm_transform = sign_algorithm_transform_map.get(sign_algorithm, xmlsec.Transform.RSA_SHA1)

        signature = OneLogin_Saml2_Utils.sign_binary(msg, key, sign_algorithm_transform, self.__settings.is_debug_active())
        data['Signature'] = OneLogin_Saml2_Utils.b64encode(signature)
        data['SigAlg'] = sign_algorithm

def get_response(self, deflate=True):
        """
        Returns a Logout Response object.
        :param deflate: It makes the deflate process optional
        :type: bool
        :return: Logout Response maybe deflated and base64 encoded
        :rtype: string
        """
        if deflate:
            response = OneLogin_Saml2_Utils.deflate_and_base64_encode(self.__logout_response)
        else:
            response = OneLogin_Saml2_Utils.b64encode(self.__logout_response)
        return response

def get_request(self, deflate=True):
        """
        Returns unsigned AuthnRequest.
        :param deflate: It makes the deflate process optional
        :type: bool
        :return: AuthnRequest maybe deflated and base64 encoded
        :rtype: str object
        """
        if deflate:
            request = OneLogin_Saml2_Utils.deflate_and_base64_encode(self.__authn_request)
        else:
            request = OneLogin_Saml2_Utils.b64encode(self.__authn_request)
        return request

def get_request(self, deflate=True):
        """
        Returns the Logout Request defated, base64encoded
        :param deflate: It makes the deflate process optional
        :type: bool
        :return: Logout Request maybe deflated and base64 encoded
        :rtype: str object
        """
        if deflate:
            request = OneLogin_Saml2_Utils.deflate_and_base64_encode(self.__logout_request)
        else:
            request = OneLogin_Saml2_Utils.b64encode(self.__logout_request)
        return request