code: public static Bson type(final String fieldName, final String type) {
          return new OperatorFilter<BsonString>("$type", fieldName, new BsonString(type));
      }
docs: Creates a filter that matches all documents where the value of the field is of the specified BSON type.
  
  @param fieldName the field name
  @param type      the string representation of the BSON type
  @return the filter
  @mongodb.driver.manual reference/operator/query/type $type