(self, name, spec_path_lists, exists)
return os.pathsep.join(unique_paths)
Given an environment variable name and specified paths,
        return a pathsep-separated string of paths containing
        unique, extant, directories from those paths and from
        the environment variable. Raise an error if no paths
        are resolved.
Given an environment variable name and specified paths,
        return a pathsep-separated string of paths containing
        unique, extant, directories from those paths and from
        the environment variable. Raise an error if no paths
        are resolved.
Given an environment variable name and specified paths return a pathsep - separated string of paths containing unique extant directories from those paths and from the environment variable . Raise an error if no paths are resolved .
def _build_paths(self, name, spec_path_lists, exists):
        """
        Given an environment variable name and specified paths,
        return a pathsep-separated string of paths containing
        unique, extant, directories from those paths and from
        the environment variable. Raise an error if no paths
        are resolved.
        """
        # flatten spec_path_lists
        spec_paths = itertools.chain.from_iterable(spec_path_lists)
        env_paths = safe_env.get(name, '').split(os.pathsep)
        paths = itertools.chain(spec_paths, env_paths)
        extant_paths = list(filter(os.path.isdir, paths)) if exists else paths
        if not extant_paths:
            msg = "%s environment variable is empty" % name.upper()
            raise distutils.errors.DistutilsPlatformError(msg)
        unique_paths = self._unique_everseen(extant_paths)
        return os.pathsep.join(unique_paths)
def _build_paths ( self , name , spec_path_lists , exists ) : # flatten spec_path_lists spec_paths = itertools . chain . from_iterable ( spec_path_lists ) env_paths = safe_env . get ( name , '' ) . split ( os . pathsep ) paths = itertools . chain ( spec_paths , env_paths ) extant_paths = list ( filter ( os . path . isdir , paths ) ) if exists else paths if not extant_paths : msg = "%s environment variable is empty" % name . upper ( ) raise distutils . errors . DistutilsPlatformError ( msg ) unique_paths = self . _unique_everseen ( extant_paths ) return os . pathsep . join ( unique_paths )