simple recursive tree display

display.py

tree = [1, [2, [10, 3, 4], [11, 5, 6]], [12, 7,8]]


def display(t, indent=0):
    if isinstance(t, list):
        print ' '*indent, t[0]
        display(t[1], indent+4)
        display(t[2], indent+4)
    else:
        print ' '*indent, t

display(tree)