Along with the output routines like poutput, pwarning, etc you could add a pretty print output. The alternative is the caller has to use pprint.pformat to pretty print the data before sending it to ...

python3 -c "import pprint,re;exec('class D(object):\\n def __init__(self,n):self.n=n\\n def __call__(self,*a,**k):return(self.n,a,k)\\nclass S(dict):\\n def ...