def fetch(
            self,
            url,
            filename=None,
            decompress=False,
            force=False,
            timeout=None,
            use_wget_if_available=True):
        """
        Return the local path to the downloaded copy of a given URL.
        Don't download the file again if it's already present,
        unless `force` is True.
        """
        key = (url, decompress)
        if not force and key in self._local_paths:
            path = self._local_paths[key]
            if exists(path):
                return path
            else:
                del self._local_paths[key]
        path = download.fetch_file(
            url,
            filename=filename,
            decompress=decompress,
            subdir=self.subdir,
            force=force,
            timeout=timeout,
            use_wget_if_available=use_wget_if_available)

        self._local_paths[key] = path
        return path
def fetch ( self , url , filename = None , decompress = False , force = False , timeout = None , use_wget_if_available = True ) : key = ( url , decompress ) if not force and key in self . _local_paths : path = self . _local_paths [ key ] if exists ( path ) : return path else : del self . _local_paths [ key ] path = download . fetch_file ( url , filename = filename , decompress = decompress , subdir = self . subdir , force = force , timeout = timeout , use_wget_if_available = use_wget_if_available ) self . _local_paths [ key ] = path return path
Return the local path to the downloaded copy of a given URL.
        Don't download the file again if it's already present,
        unless `force` is True.