PL/Python3 - Concatenate PLyResults - python-3.x

Question

I'm wondering if it's possible to concatenate PLyResults somehow inside a function. For example, let's say that firstly I have a function _get_data that, given a tuple (id, index) returns a table of values:
CREATE OR REPLACE FUNCTION _get_data(id bigint, index bigint):
RETURNS TABLE(oid bigint, id bigint, val double precision) AS
$BODY$
#...process for fetching the data, irrelevant for the question.
return recs
$BODY$
LANGUAGE plpython3u;
Now I would like to be able to create a generic function defined as such, that fetches data between two boundaries for a given ID, and uses the previous function to fetch data individually and then aggregate the results somehow:
CREATE OR REPLACE FUNCTION get_data(id bigint, lbound bigint, ubound bigint)
RETURNS TABLE(oid bigint, id bigint, val double precision) AS
$BODY$
concatenated_recs = [] #<-- For the sake of argument.
plan = plpy.prepare("SELECT oid, id, val FROM _get_data($1, $2);", ['bigint', 'bigint'])
for i in range(lbound, ubound+1):
recs = plpy.execute(plan, [id, i]) # <-- Records fetched individually
concatenated_recs += [recs] #<-- Not sure how to concatenate them...
return concatenated_recs
$BODY$
LANGUAGE plpython3u;

Answer 1

Perhaps I am missing something, but the answer you gave looks like a slower, more complicated version of this query:
SELECT oid, id, val
FROM generate_series(your_lower_bound, your_upper_bound) AS g(i),
_get_data(your_id, i);
You could put that in a simple SQL function with no loops or temporary tables:
CREATE OR REPLACE FUNCTION get_data(id bigint, lbound bigint, ubound bigint)
RETURNS TABLE(oid bigint, id bigint, val double precision) AS
$BODY$
SELECT oid, id, val
FROM generate_series(lbound, ubound) AS g(i),
_get_data(id, i);
$BODY$ LANGUAGE SQL;

Answer 2

Although I wasn't able to find a way to concatenate the results from the PL/Python documentation, and as of 06-2019, I'm not sure if the language supports this resource, I could solve it by creating a temp table, inserting the records in it for each iteration and then returning the full table:
CREATE OR REPLACE FUNCTION get_data(id bigint, lbound bigint, ubound bigint)
RETURNS TABLE(oid bigint, id bigint, val double precision) AS
$BODY$
#Creates the temp table
plpy.execute("""CREATE TEMP TABLE temp_results(oid bigint, id bigint, val double precision)
ON COMMIT DROP""")
plan = plpy.prepare("INSERT INTO temp_results SELECT oid, id, val FROM _get_data($1, $2);",
['bigint', 'bigint'])
#Inserts the results in the temp table
for i in range(lbound, ubound+1):
plpy.execute(plan, [id, i])
#Returns the whole table
recs = plpy.execute("SELECT * FROM temp_results")
return recs
$BODY$
LANGUAGE plpython3u;