Get the XML (as string) of all resources of type 'string'.
        This is a combined variant, which has all locales and all package names
        stored.

def get_strings_resources(self):
        """
        Get the XML (as string) of all resources of type 'string'.
        This is a combined variant, which has all locales and all package names
        stored.
        """
        self._analyse()

        buff = '<?xml version="1.0" encoding="utf-8"?>\n'

        buff += "<packages>\n"
        for package_name in self.get_packages_names():
            buff += "<package name=\"%s\">\n" % package_name

            for locale in self.get_locales(package_name):
                buff += "<locale value=%s>\n" % repr(locale)

                buff += '<resources>\n'
                try:
                    for i in self.values[package_name][locale]["string"]:
                        buff += '<string name="{}">{}</string>\n'.format(i[0], escape(i[1]))
                except KeyError:
                    pass

                buff += '</resources>\n'
                buff += '</locale>\n'

            buff += "</package>\n"

        buff += "</packages>\n"

        return buff.encode('utf-8')