Modify coordinate string in parsed KML file [closed]

I am new to Python. I found this code on the internet to parse names and coordinate strings from KML files and write them into a .csv file. Works excellent! However, for my purpose, I need to convert the coordinate string to GeoJSON as output. For my GeoJSON format I need to remove the height/accuracy from each coordinate. So I only need the lat,lon coordinates and want to remove the height/accuracy. Besides that I need to enclose each individual lat,lon coordinate with square brackets []. So, for example, I now have this output format for my coordinate string:

-89.42462055297086,16.35478756523923,507.7306687727497
-89.41330216185102,16.33874177258091,521.3689105782825

And need to convert this coordinate string to this format:

[-89.42462055297086,16.35478756523923],[-89.41330216185102,16.33874177258091]

Below is the code I am using now. I want to add some code to create the GeoJSON coordinate string format I need. How can I do this?

import xml.sax, xml.sax.handler

inputname = 'Test4.kml'
kml = open(inputname, 'r')


class PlacemarkHandler(xml.sax.handler.ContentHandler):
    def __init__(self):
        self.inName = False # handle XML parser events
        self.inPlacemark = False
        self.mapping = {}
        self.buffer = ""
        self.name_tag = ""

    def startElement(self, name, attributes):
        if name == "Placemark": # on start Placemark tag
            self.inPlacemark = True
            self.buffer = ""
        if self.inPlacemark:
            if name == "name": # on start title tag
                self.inName = True # save name text to follow

    def characters(self, data):
        if self.inPlacemark: # on text within tag
            self.buffer += data # save text if in title

    def endElement(self, name):
        self.buffer = self.buffer.strip('\n\t')

        if name == "Placemark":
            self.inPlacemark = False
            self.name_tag = "" #clear current name

        elif name == "name" and self.inPlacemark:
            self.inName = False # on end title tag
            self.name_tag = self.buffer.strip()
            self.mapping[self.name_tag] = {}

        elif self.inPlacemark:
            if name in self.mapping[self.name_tag]:
                self.mapping[self.name_tag][name] += self.buffer
            else:
                self.mapping[self.name_tag][name] = self.buffer
        self.buffer = ""

parser = xml.sax.make_parser()
handler = PlacemarkHandler()
parser.setContentHandler(handler)
parser.parse(kml)

def build_table(mapping):
   sep = ';'

   output = 'Name' + sep + 'Coordinates' + sep + 'test column\n'
   points = ''
   lines = ''
   shapes = ''
   for key in mapping:
       coord_str = '{"type":"FeatureCollection","features":[{"type":"Feature","geometry":{"type":"Polygon","coordinates":[[[' + mapping[key]['coordinates'] + ']]]}}]}' + sep

       if 'LookAt' in mapping[key]: #points
           points += key + sep + coord_str + "\n"
       elif 'LineString' in mapping[key]: #lines
           lines += key + sep + coord_str + "\n"
       else: #shapes
           shapes += key + sep + 'coord_str\n'
   output += points + lines + shapes
   return output

outstr = build_table(handler.mapping) 
out_filename = 'output-result.csv'#output filename same as input plus .csv 
f = open(out_filename, "w") 
f.write(outstr) 
f.close() 
print(outstr)
°°°