"""Two predicates that can help avoid unnecessary disk I/O by
detecting if a particular file is identical to the contents about to
be written or if a particular directory already contains a file that
is identical to the one to be written. See class docs below for
"""Two predicates that can help avoid unnecessary disk I/O by
detecting if a particular file is identical to the contents about to
be written or if a particular directory already contains a file that
is identical to the one to be written. See class docs below for