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 _ignoring_sigint(self):
        with self._ignore_sigint_lock:
            self._check_sigint_gate_is_correct()
            self._threads_ignoring_sigint += 1
        try:
            yield
        finally:
            with self._ignore_sigint_lock:
                self._threads_ignoring_sigint -= 1
                self._check_sigint_gate_is_correct()