code: def flatten_list_abundance(node: ListAbundance) -> ListAbundance:
      
      return node.__class__(list(chain.from_iterable(
          (
              flatten_list_abundance(member).members
              if isinstance(member, ListAbundance) else
              [member]
          )
          for member in node.members
      )))
docs: Flattens the complex or composite abundance.