Filter the contacts on the basis of attributes. Allowed operator: equals. For multiple-choice options, the filter will apply an AND condition between the options. For category attributes, the filter will work with both id and value. (e.g. filter=equals(FIRSTNAME,"Antoine"), filter=equals(B1, true), filter=equals(DOB, "1989-11-23"), filter=equals(GENDER, "1"), filter=equals(GENDER, "MALE"), filter=equals(COUNTRY,"USA, INDIA")