code: def list_policy_versions(policy_name,
                    region=None, key=None, keyid=None, profile=None):
      '''
      List versions of a policy.
  
      CLI Example:
  
      .. code-block:: bash
  
          salt myminion boto_iam.list_policy_versions mypolicy
      '''
      conn = _get_conn(region=region, key=key, keyid=keyid, profile=profile)
  
      policy_arn = _get_policy_arn(policy_name, region, key, keyid, profile)
      try:
          ret = conn.list_policy_versions(policy_arn)
          return ret.get('list_policy_versions_response', {}).get('list_policy_versions_result', {}).get('versions')
      except boto.exception.BotoServerError as e:
          log.debug(e)
          log.error('Failed to list versions for IAM policy %s.', policy_name)
          return [f list_policy_versions(policy_name,
                    region=None, key=None, keyid=None, profile=None):
      '''
      List versions of a policy.
  
      CLI Example:
  
      .. code-block:: bash
  
          salt myminion boto_iam.list_policy_versions mypolicy
      '''
      conn = _get_conn(region=region, key=key, keyid=keyid, profile=profile)
  
      policy_arn = _get_policy_arn(policy_name, region, key, keyid, profile)
      try:
          ret = conn.list_policy_versions(policy_arn)
          return ret.get('list_policy_versions_response', {}).get('list_policy_versions_result', {}).get('versions')
      except boto.exception.BotoServerError as e:
          log.debug(e)
          log.error('Failed to list versions for IAM policy %s.', policy_name)
          return []
docs: List versions of a policy.
  
      CLI Example:
  
      .. code-block:: bash
  
          salt myminion boto_iam.list_policy_versions mypolicy