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 uipath(self, f):
        """Convert repo path to a display path.  If patterns or -I/-X were used
        to create this matcher, the display path will be relative to cwd.
        Otherwise it is relative to the root of the repo."""
        return (self._relativeuipath and self.rel(f)) or self.abs(f)