(python) Using ToList output as input for AsSingleton or AsList in Apache Beam

[Bruno Dias]

I'm getting an unexpected error when I try to use the output of
beam.combiners.ToList as the input of beam.pvalue.AsSingleton or
beam.pvalue.AsList in order to experiment with side inputs. I was able to
use single numbers (e.g.: the mean of a list) as a side input but, for
lists and dictionaries, I'm getting exceptions. For
beam.pvalue.AsSingleton, I get this: https://www.pastiebin.com/5cb475355dedf

For beam.pvalue.AsList, I get https://www.pastiebin.com/5cb475f0e7f96.

This is the code I'm running: https://www.pastiebin.com/5cb4760eb9abe.

Replace beam.pvalue.AsSingleton with beam.pvalue.AsList to get the other
error. I'm using Apache Beam python SDK version 2.11.0.