def coerce(cls, string):
        """Create a :class:`Requirement` object from a given package spec."""
        match = re.match(cls.spec_regex, string)
        if not match:
            raise InvalidRequirementSpecError("could not parse requirement")
        package = match.group(1)
        if all(match.group(2, 3)):
            version = "".join(match.group(2, 3))
        else:
            version = None
        return cls(package, version)
def _handle_sigint_if_enabled(self, signum, _frame):
        with self._ignore_sigint_lock:
            self._check_sigint_gate_is_correct()
            threads_ignoring_sigint = self._threads_ignoring_sigint
            ignoring_sigint_v2_engine = self._ignoring_sigint_v2_engine
        if threads_ignoring_sigint == 0 and not ignoring_sigint_v2_engine:
            self.handle_sigint(signum, _frame)