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 remove_duplicates(self):
        if self.ui.chkBRemoveDuplicates.isChecked():
            for lbl in self.message.message_type:
                seq = lbl.fuzz_values[:]
                seen = set()
                add_seen = seen.add
                lbl.fuzz_values = [l for l in seq if not (l in seen or add_seen(l))]