public static Function getFunctionInstance(Serializable function) {
    Function functionInstance = null;
    if (function instanceof String) {
      functionInstance = FunctionService.getFunction((String) function);
      Assert.assertTrue(functionInstance != null,
          "Function " + function + " is not registered on this node ");
    } else {
      functionInstance = (Function) function;
    }
    return functionInstance;
  }
A utility method to retrieve all child partitioned regions that are directly colocated to the
specified partitioned region.<br>
<p>
For example, shipmentPR is colocated with orderPR and orderPR is colocated with customerPR.
<br>
getColocatedChildRegions(customerPR) will return List{orderPR}<br>
getColocatedChildRegions(orderPR) will return List{shipmentPR}<br>
getColocatedChildRegions(shipmentPR) will return empty List{}<br>

@return list of all child partitioned regions colocated with the region
@since GemFire 5.8Beta
geode-core/src/main/java/org/apache/geode/internal/cache/ColocationHelper.java