def _convert_xml_to_signed_identifiers(response):
if response is None or response.body is None:<EOL><INDENT>return None<EOL><DEDENT>list_element = ETree.fromstring(response.body)<EOL>signed_identifiers = _dict()<EOL>for signed_identifier_element in list_element.findall('<STR_LIT>'):<EOL><INDENT>id = signed_identifier_element.find('<STR_LIT>').text<EOL>access_policy = AccessPolicy()<EOL>access_policy_element = signed_identifier_element.find('<STR_LIT>')<EOL>if access_policy_element is not None:<EOL><INDENT>start_element = access_policy_element.find('<STR_LIT>')<EOL>if start_element is not None:<EOL><INDENT>access_policy.start = parser.parse(start_element.text)<EOL><DEDENT>expiry_element = access_policy_element.find('<STR_LIT>')<EOL>if expiry_element is not None:<EOL><INDENT>access_policy.expiry = parser.parse(expiry_element.text)<EOL><DEDENT>access_policy.permission = access_policy_element.findtext('<STR_LIT>')<EOL><DEDENT>signed_identifiers[id] = access_policy<EOL><DEDENT>return signed_identifiers<EOL>
<?xml version="1.0" encoding="utf-8"?>
<SignedIdentifiers>
  <SignedIdentifier>
    <Id>unique-value</Id>
    <AccessPolicy>
      <Start>start-time</Start>
      <Expiry>expiry-time</Expiry>
      <Permission>abbreviated-permission-list</Permission>
    </AccessPolicy>
  </SignedIdentifier>
</SignedIdentifiers>