added note on sort_signals and prune_choices to dump_file
@@ -230,6 +230,8 @@ def dump_file(database,
>>> db = cantools.database.load_file('foo.dbc')
>>> cantools.database.dump_file(db, 'bar.dbc')
+ Pass `sort_signals=None, prune_choices=False` to load_file
+ in order to minimize the differences between foo.dbc and bar.dbc.
"""
database_format, encoding = _resolve_database_format_and_encoding(
