Lindenmayer System Python Fractral Tree
Personally I don't like multiples if statements inside a for, here is my suggestion:

def handler_option_c(t, b):
    t.pencolor("brown")
    t.forward(100) # Change this to modify the size of the tree

handlers = { "c" : handler_option_c, ....


And you do the same for the other options, and then on your main

for c in code:
    handlers[c](t, branch)


Or you can put that on a lambda also