'Returns a list of the XML representations of each of the given
properties. Ignores properties that don\'t exist in this entity.
Arg:
properties: string or list of strings
Returns:
list of strings'

def _PropertiesToXml(self, properties):

    xml_properties = []
    for propname in properties:
        if (not self.has_key(propname)):
            continue
        propname_xml = saxutils.quoteattr(propname)
        values = self[propname]
        if (isinstance(values, list) and (not values)):
            continue
        if (not isinstance(values, list)):
            values = [values]
        proptype = datastore_types.PropertyTypeName(values[0])
        proptype_xml = saxutils.quoteattr(proptype)
        escaped_values = self._XmlEscapeValues(propname)
        open_tag = (u'<property    name=%s    type=%s>' % (propname_xml, proptype_xml))
        close_tag = u'</property>'
        xml_properties += [((open_tag + val) + close_tag) for val in escaped_values]
    return xml_properties
