`object
method file_exists : 'a OASISFileSystem.filename -> bool
method open_in :
?mode:Stdlib.open_flag list ->
?perm:int -> 'a OASISFileSystem.filename -> OASISFileSystem.reader
method open_out :
?mode:Stdlib.open_flag list ->
?perm:int -> 'a OASISFileSystem.filename -> OASISFileSystem.writer
method remove : 'a OASISFileSystem.filename -> unit
method string_of_filename : 'a OASISFileSystem.filename -> string
end`