• The reader now supports pure Python file and memory modes. If you are not
  using the C extension and your Python does not provide the mmap module,
  the file mode will be used by default. You can explicitly set the mode using
  the mode keyword argument with the MODE_AUTO, MODE_MMAP,
  MODE_MMAP_EXT, MODE_FILE, and MODE_MEMORY constants exported by
  geoip2.database.