import zipfile
import io


def _make_zip_file() -> zipfile.ZipFile:
  """Returns an in-memory zip file."""
  data = io.BytesIO()
  zf = zipfile.ZipFile(data, 'w')
  zf.writestr('a.txt', b'content of a')
  zf.writestr('b/c.txt', b'content of c')
  zf.writestr('b/d/e.txt', b'content of e')
  zf.writestr('b/f.txt', b'content of f')
  zf.writestr('g/h/i.txt', b'content of i')
  zf.filename = 'alpharep.zip'
  return zf