title: Don't check f.loc in _get_extraction_protocol_with_magic_number
comments: _The documentation is not available anymore as the PR was closed or merged._
body: `f.loc` doesn't always exist for file-like objects in python. I removed it since it was not necessary anyway (we always seek the file to 0 after reading the magic number)
  
  Fix https://github.com/huggingface/datasets/issues/4310