Regex package:bson

The first string is the regex pattern, the second is the regex options string. Options are identified by characters, which must be listed in alphabetical order. Valid options are *i* for case insensitive matching, *m* for multiline matching, *x* for verbose mode, *l* to make \w, \W, etc. locale dependent, *s* for dotall mode ("." matches everything), and *u* to make \w, \W, etc. match unicode.