How to use the moltemplate.ttree.InstanceObj function in moltemplate

if sys.version < '2.6':
        raise InputError(
            'Error: Alas, you must upgrade to a newer version of python.')

    try:

        #settings = BasicUISettings()
        #BasicUIParseArgs(sys.argv, settings)
        settings = LttreeSettings()
        LttreeParseArgs([arg for arg in sys.argv],  #(deep copy of sys.argv)
                        settings, main=True, show_warnings=True)

        # Data structures to store the class definitionss and instances
        g_objectdefs = StaticObj('', None)  # The root of the static tree
        # has name '' (equivalent to '/')
        g_objects = InstanceObj('', None)  # The root of the instance tree
        # has name '' (equivalent to '/')

        # A list of commands to carry out
        g_static_commands = []
        g_instance_commands = []

        BasicUI(settings,
                g_objectdefs,
                g_objects,
                g_static_commands,
                g_instance_commands)

        # Interpret the the commands.  (These are typically write() or
        # write_once() commands, rendering templates into text.
        # This step also handles coordinate transformations and delete commands.
        # Coordinate transformations can be applied to the rendered text

# ---- Coordinates of the atoms, must be rotated 
            # and translated after rendering.
            # In addition, other vectors (dipoles, ellipsoid orientations)
            # must be processed.
            # This requires us to re-parse the contents of this text
            # (after it has been rendered), and apply these transformations
            # before passing them on to the caller.
            if command.filename == data_atoms:
                text = TransformAtomText(text, matrix_stack.M)

            files_content[command.filename].append(text)


        elif isinstance(command, ScopeBegin):

            if isinstance(command.node, InstanceObj):
                if ((command.node.children != None) and 
                    (len(command.node.children) > 0)):
                    matrix_stack.PushStack(command.node)

            # "command_list" is a long list of commands.
            # ScopeBegin and ScopeEnd are (usually) used to demarcate/enclose
            # the commands which are issued for a single class or 
            # class instance.  _ExecCommands() carries out the commands for 
            # a single class/instance.  If we reach a ScopeBegin(), 
            # then recursively process the commands belonging to the child.
            index = _ExecCommands(command_list,
                                  index,
                                  files_content, 
                                  settings,
                                  matrix_stack, 
                                  command.node,

sys.stderr.write(g_program_name+' v'+g_version_str+' '+g_date_str+' ')
    sys.stderr.write('\n(python version '+str(sys.version)+')\n')
    if sys.version < '2.6':
        raise InputError('Error: Alas, you must upgrade to a newever version of python.')

    try:

        #settings = BasicUISettings()
        #BasicUIParseArgs(sys.argv, settings)
        settings = EttreeSettings()
        EttreeParseArgs(sys.argv, settings)

        # Data structures to store the class definitionss and instances
        g_objectdefs = StaticObj('', None) # The root of the static tree
                                           # has name '' (equivalent to '/')
        g_objects    = InstanceObj('', None) # The root of the instance tree
                                             # has name '' (equivalent to '/')

        # A list of commands to carry out
        g_static_commands = []
        g_instance_commands = []


        BasicUI(settings,
                g_objectdefs, 
                g_objects,
                g_static_commands,
                g_instance_commands)

        # Now, carry out the commands
        # This involves rendering the templates and post-processing them.

matrix_stack.PushCommandsLeft(ppcommand.contents,
                                                      ppcommand.srcloc,
                                                      xcm,
                                                      which_stack=command.context_node)
                    files_content[data_atoms] = \
                        TransformAtomText(files_content[data_atoms],
                                          matrix_stack.M, settings)
                    files_content[data_ellipsoids] = \
                        TransformEllipsoidText(files_content[data_ellipsoids],
                                               matrix_stack.M, settings)

                for ppcommand in postprocessing_commands:
                    matrix_stack.Pop(which_stack=command.context_node)
                    #(same as PopRight())

            if isinstance(command.node, InstanceObj):
                if ((command.node.children != None) and
                        (len(command.node.children) > 0)):
                    matrix_stack.PopStack()

            # "ScopeEnd"  means we're done with this class/instance.
            break

        else:
            assert(False)
            # no other command types allowed at this point

    # After processing the commands in this list,
    # merge the templates with the callers template list
    for filename, tmpl_list in files_content.items():
        global_files_content[filename] += \
            files_content[filename]

# This requires us to re-parse the contents of this text
            # (after it has been rendered), and apply these transformations
            # before passing them on to the caller.
            if command.filename == data_atoms:
                text = TransformAtomText(text, matrix_stack.M, settings)
            elif command.filename == data_ellipsoids:
                text = TransformEllipsoidText(text, matrix_stack.M, settings)
            if command.filename == data_masses:
                text = AddAtomTypeComments(tmpl_list,
                                           substitute_vars,
                                           settings.print_full_atom_type_name_in_masses)
            files_content[command.filename].append(text)

        elif isinstance(command, ScopeBegin):

            if isinstance(command.node, InstanceObj):
                if ((command.node.children != None) and
                        (len(command.node.children) > 0)):
                    matrix_stack.PushStack(command.node)

            # "command_list" is a long list of commands.
            # ScopeBegin and ScopeEnd are (usually) used to demarcate/enclose
            # the commands which are issued for a single class or
            # class instance.  _ExecCommands() carries out the commands for
            # a single class/instance.  If we reach a ScopeBegin(),
            # then recursively process the commands belonging to the child.
            index = _ExecCommands(command_list,
                                  index,
                                  files_content,
                                  settings,
                                  matrix_stack,
                                  command.node,