can it compress an existing file like gzip??

[javiercr2020]

Can use use the same syntax as gzip to compress an existing file? this does not work

import mgzip
import shutil

with open(filename, 'rb') as f_in:
    with mgzip.open(filename+'.gz', "wt", thread=8, blocksize=2*10**8) as f_out:
        shutil.copyfileobj(f_in, f_out)

[cielavenir]

@javiercr2020 it works when I change the mode to "wb".