def append_approx(data=bpy.data, use_fake_user=False):
    in_sockets = [
        {'name': 'A'},
        {'name': 'B'},
        {'name': 'Tolerance',
         'default_value': 0.0001,
         'min_value': 0.0}
    ]

    out_sockets = [
        {'name': 'Boolean',
         'min_value': 0.0,
         'max_value': 1.0}
    ]

    # Create group.
    approx_group = append_group_node(name='Approx', data=data, use_fake_user=use_fake_user, in_sockets=in_sockets, out_sockets=out_sockets)
    
    # Create math nodes.
    nodes = approx_group.nodes
    subt = append_math_node(nodes, operation='SUBTRACT')
    absv = append_math_node(nodes, operation='ABSOLUTE')
    gt = append_math_node(nodes, operation='GREATER_THAN')

    # Link nodes.
    links = approx_group.links
    links.new(absv.inputs[0], subt.outputs[0])
    links.new(gt.inputs[1], absv.outputs[0])

    # Link to group inputs.
    app_input = approx_group.nodes['Group Input']
    links.new(subt.inputs[0], app_input.outputs[0])
    links.new(subt.inputs[1], app_input.outputs[1])
    links.new(gt.inputs[0], app_input.outputs[2])

    # Link to group outputs.
    app_output = approx_group.nodes['Group Output']
    links.new(app_output.inputs[0], gt.outputs[0])

    return approx_group