code: @Override
      public ListPolicyVersionsResult listPolicyVersions(ListPolicyVersionsRequest request) {
          request = beforeClientExecution(request);
          return executeListPolicyVersions(request);
      }
docs: <p>
  Lists information about the versions of the specified managed policy, including the version that is currently set
  as the policy's default version.
  </p>
  <p>
  For more information about managed policies, see <a
  href="https://docs.aws.amazon.com/IAM/latest/UserGuide/policies-managed-vs-inline.html">Managed Policies and
  Inline Policies</a> in the <i>IAM User Guide</i>.
  </p>
  
  @param listPolicyVersionsRequest
  @return Result of the ListPolicyVersions operation returned by the service.
  @throws NoSuchEntityException
  The request was rejected because it referenced a resource entity that does not exist. The error message
  describes the resource.
  @throws InvalidInputException
  The request was rejected because an invalid or out-of-range value was supplied for an input parameter.
  @throws ServiceFailureException
  The request processing has failed because of an unknown error, exception or failure.
  @sample AmazonIdentityManagement.ListPolicyVersions
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/iam-2010-05-08/ListPolicyVersions" target="_top">AWS API
  Documentation</a>