code: public ServiceFuture<PolicyDefinitionInner> getAtManagementGroupAsync(String policyDefinitionName, String managementGroupId, final ServiceCallback<PolicyDefinitionInner> serviceCallback) {
          return ServiceFuture.fromResponse(getAtManagementGroupWithServiceResponseAsync(policyDefinitionName, managementGroupId), serviceCallback);
      }
docs: Gets the policy definition at management group level.
  
  @param policyDefinitionName The name of the policy definition to get.
  @param managementGroupId The ID of the management group.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object