docs: def update_assume_role_policy(role_name, policy_document, region=None,
                                key=None, keyid=None, profile=None):
      '''
      Update an assume role policy for a role.
  
      .. versionadded:: 2015.8.0
  
      CLI Example:
  
      .. code-block:: bash
  
          salt myminion boto_iam.update_assume_role_policy myrole '{"Statement":"..."}'
      '''
      conn = _get_conn(region=region, key=key, keyid=keyid, profile=profile)
  
      if isinstance(policy_document, six.string_types):
          policy_document = salt.utils.json.loads(policy_document,
                                       object_pairs_hook=odict.OrderedDict)
      try:
          _policy_document = salt.utils.json.dumps(policy_document)
          conn.update_assume_role_policy(role_name, _policy_document)
          log.info('Successfully updated assume role policy for IAM role %s.', role_name)
          return True
      except boto.exception.BotoServerError as e:
          log.error(e)
          log.error('Failed to update assume role policy for IAM role %s.', role_name)
          return False