def __init__(self, package, version):
        """Construct a new requirement.

        :param package: the package name.
        :param version: a semver compatible version specification.
        """
        self.package = package
        self.version = version
        if self.version and not re.match(r"[<=>~]", version[:2]):
            self.version = "=={}".format(self.version)
def ngettext(self, singular: str, plural: str, lang: str = None, n=1):
        """
        Plural translations
        """
        if lang is None:
            lang = self.context_lang.get()

        if lang not in self.translations:
            if n == 1:
                return singular
            return plural

        translator = self.translations[lang]
        return translator.ngettext(singular, plural, n)