code: public Observable<PolicySetDefinitionInner> getAsync(String policySetDefinitionName) {
          return getWithServiceResponseAsync(policySetDefinitionName).map(new Func1<ServiceResponse<PolicySetDefinitionInner>, PolicySetDefinitionInner>() {
              @Override
              public PolicySetDefinitionInner call(ServiceResponse<PolicySetDefinitionInner> response) {
                  return response.body();
              }
          });
      }
docs: Retrieves a policy set definition.
  This operation retrieves the policy set definition in the given subscription with the given name.
  
  @param policySetDefinitionName The name of the policy set definition to get.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PolicySetDefinitionInner object