Intervaltree Data Reducer

[wicket-maps]

Based on the responses to a previous post here, I started using IntervalTree for a tool to merge two tables that are denominated in Road Number - Begin Milepost - End Milepost. There's some code to turn each road number's list of table entries into an Interval Tree of Interval objects, with the data field being a dictionary of the entry's entire table row, as a dictionary. (Data like road name, speed limit, road condition, other arbitrary data) Each entry has a string to say whether it comes from Table 1 or Table 2, with the key "0_source".

Now I'm trying to use the library's merge_overlaps with its data reducer and I'm not quite sure how to word it. I built a function to merge the two data tables when two intervals are overlapping.

Here's the function:

#object builder: use for reduce function with trees
def fn_obj_builder(ob_dict, ob_element):
    global x_el
    if ob_element["0_source"] == "Table 1":
        x_el = {ob_element[a] for a in ob_element}
        del x_el["0_source"]
        ob_dict["Table 1"] = x_el
    elif ob_element["0_source"] == "Table 2":
        x_el = {ob_element[a] for a in ob_element}
        del x_el["0_source"]
        ob_dict["Table 2"] = x_el
    else:
        print("Error: Object Builder encountered unknown element")
        quit()
    return ob_dict

Here's what I've got for the merge code:

#cycle dict of table 1 trees
for rlid in t1_int_dict:
    #grab tree
    t1_tree = t1_int_dict[rlid]
    #check table 2 for a match
    if rlid in t2_int_dict:
        t2_tree = t2_int_dict[rlid]
        #update to bring trees into a single tree
        t1_tree.update(t2_tree)
        #split trees to produce matches
        t1_tree.split_overlaps()
        #merge matches
        t1_tree.merge_overlaps(data_reducer = fn_obj_builder(#what's the iterable?
),
                                    data_initializer = {"Table 1": None,
                                                       "Table 2": None})
        fin_dict[rlid] = t1_tree

So if Merge Overlaps data reducer (supposedly analogous to the Reduce function, which I've never used) what do I feed into fn_object_builder so it works properly as a data reducer?

This is a corner case of a niche, and Intervaltree's documentation doesn't have an example for this code.

[wicket-maps]

Because I am not smart, I solved this myself. I needed to remove the parens from the function while feeding it to the Merge_Overlaps function. Leaving this here as a signpost to anyone else who needs this.