code: def decorate_arguments(self, arguments):
          
          arguments = list(arguments)
          for i, value in enumerate(arguments):
              is_constraint_file = (i >= 1 and match_option(arguments[i - 1], '-c', '--constraint'))
              is_requirement_file = (i >= 1 and match_option(arguments[i - 1], '-r', '--requirement'))
              if not is_constraint_file and not is_requirement_file and os.path.isfile(value):
                  arguments[i] = '%s#md5=%s' % (create_file_url(value), hash_files('md5', value))
          return arguments
docs: Change pathnames of local files into ``file://`` URLs with ``#md5=...`` fragments.
  
          :param arguments: The command line arguments to ``pip install ...`` (a
                            list of strings).
          :returns: A copy of the command line arguments with pathnames of local
                    files rewritten to ``file://`` URLs.
  
          When pip-accel calls pip to download missing distribution archives and
          the user specified the pathname of a local distribution archive on the
          command line, pip will (by default) *not* copy the archive into the
          download directory if an archive for the same package name and
          version is already present.
  
          This can lead to the confusing situation where the user specifies a
          local distribution archive to install, a different (older) archive for
          the same package and version is present in the download directory and
          `pip-accel` installs the older archive instead of the newer archive.
  
          To avoid this confusing behavior, the :func:`decorate_arguments()`
          method rewrites the command line arguments given to ``pip install`` so
          that pathnames of local archives are changed into ``file://`` URLs that
          include a fragment with the hash of the file's contents. Here's an
          example:
  
          - Local pathname: ``/tmp/pep8-1.6.3a0.tar.gz``
          - File URL: ``file:///tmp/pep8-1.6.3a0.tar.gz#md5=19cbf0b633498ead63fb3c66e5f1caf6``
  
          When pip fills the download directory and encounters a previously
          cached distribution archive it will check the hash, realize the
          contents have changed and replace the archive in the download
          directory.