The second argument, if present, specifies the file location to copy to (if
absent, the location will be a tempfile with a generated name). The third
- argument, if present, is a hook function that will be called once on
+ argument, if present, is a callable that will be called once on
establishment of the network connection and once after each block read
- thereafter. The hook will be passed three arguments; a count of blocks
+ thereafter. The callable will be passed three arguments; a count of blocks
transferred so far, a block size in bytes, and the total size of the file. The
third argument may be ``-1`` on older FTP servers which do not return a file
size in response to a retrieval request.