Wrote 8 bytes
Integer() = 1
b.TypeString()   Base(null)
di.TypeString()  DerivedI(null, 1)
dss.TypeString() DerivedSS(null, left, right)
f(b)           Base(null)
f(di)          DerivedI(null, 1)
f(dss)         DerivedSS(null, left, right)
TextOutput constructor
foo
bar
num_chars = 42
i = 43