(
            self, req, working_set, installer=None, replace_conflicting=False)
return self.obtain(req, installer)
Find distribution best matching `req` and usable on `working_set`

        This calls the ``find(req)`` method of the `working_set` to see if a
        suitable distribution is already active.  (This may raise
        ``VersionConflict`` if an unsuitable version of the project is already
        active in the specified `working_set`.)  If a suitable distribution
        isn't active, this method returns the newest distribution in the
        environment that meets the ``Requirement`` in `req`.  If no suitable
        distribution is found, and `installer` is supplied, then the result of
        calling the environment's ``obtain(req, installer)`` method will be
        returned.
Find distribution best matching `req` and usable on `working_set`
Find distribution best matching req and usable on working_set
def best_match(
            self, req, working_set, installer=None, replace_conflicting=False):
        """Find distribution best matching `req` and usable on `working_set`

        This calls the ``find(req)`` method of the `working_set` to see if a
        suitable distribution is already active.  (This may raise
        ``VersionConflict`` if an unsuitable version of the project is already
        active in the specified `working_set`.)  If a suitable distribution
        isn't active, this method returns the newest distribution in the
        environment that meets the ``Requirement`` in `req`.  If no suitable
        distribution is found, and `installer` is supplied, then the result of
        calling the environment's ``obtain(req, installer)`` method will be
        returned.
        """
        try:
            dist = working_set.find(req)
        except VersionConflict:
            if not replace_conflicting:
                raise
            dist = None
        if dist is not None:
            return dist
        for dist in self[req.key]:
            if dist in req:
                return dist
        # try to download/install
        return self.obtain(req, installer)
def best_match ( self , req , working_set , installer = None , replace_conflicting = False ) : try : dist = working_set . find ( req ) except VersionConflict : if not replace_conflicting : raise dist = None if dist is not None : return dist for dist in self [ req . key ] : if dist in req : return dist # try to download/install return self . obtain ( req , installer )