'Get a version matcher for a requirement.
:param reqt: The requirement
:type reqt: str
:return: A version matcher (an instance of
:class:`distlib.version.Matcher`).'

def get_matcher(self, reqt):

    try:
        matcher = self.scheme.matcher(reqt)
    except UnsupportedVersionError:
        name = reqt.split()[0]
        matcher = self.scheme.matcher(name)
    return matcher
