Added field output handler for date range segments based on months.

Civi/DataProcessor/FieldOutputHandler/DateMonthSegmentFieldOutputHandler.php

@@ -61,6 +61,15 @@ class DateMonthSegmentFieldOutputHandler extends AbstractSimpleSortableFieldOutp
     $this->textInRange = $configuration['text_within_range'];
   }
 
+  /**
+   * Returns the data type of this field
+   *
+   * @return String
+   */
+  protected function getType() {
+    return 'String';
+  }
+
   /**
    * Returns the formatted value
    *