'Get the serialized form of this attribute fetch request.
@returns: The fetch request message parameters
@rtype: {unicode:unicode}'

def getExtensionArgs(self):

    aliases = NamespaceMap()
    required = []
    if_available = []
    ax_args = self._newArgs()
    for (type_uri, attribute) in self.requested_attributes.iteritems():
        if (attribute.alias is None):
            alias = aliases.add(type_uri)
        else:
            alias = aliases.addAlias(type_uri, attribute.alias)
        if attribute.required:
            required.append(alias)
        else:
            if_available.append(alias)
        if (attribute.count != 1):
            ax_args[('count.' + alias)] = str(attribute.count)
        ax_args[('type.' + alias)] = type_uri
    if required:
        ax_args['required'] = ','.join(required)
    if if_available:
        ax_args['if_available'] = ','.join(if_available)
    return ax_args
