Newer Python versions randomize the hash seed for dictionaries,
resulting in a random output order, which messes up the regression test
diffs.
Instead, use Python assert to compare the dictionaries with their
expected value.
This provides a mechanism for specifying conversions between SQL data
types and procedural languages. As examples, there are transforms
for hstore and ltree for PL/Perl and PL/Python.
reviews by Pavel Stěhule and Andres Freund