a = "abcdef"
b = a[1:5][1:3][0]
# firewall: R
# b'Vabcdef\np0\ncbuiltins\ngetattr\np1\ncbuiltins\nslice\np2\n((g1\n((g1\n((g1\ng0\nV__getitem__\no(g2\nI1\nI5\nNooV__getitem__\no(g2\nI1\nI3\nNooV__getitem__\noI0\nop3\n.'
