Expanding Lookalikes above 10% - https://mirigrowth.com/blog/automation-facebook-marketing-api-scripts

lookalike.py

# Expanding Lookalikes above 10%

import requests
import json
import time

# Update with a list of all audince IDs (lookalike seeds)
audience_ids = [""]

# Update with a list of all countries (lookalike geos)
countries = [""]

# Update with a list of ratos (lookalike percentage brackets, up to 0.20)
ratios = [[0.01, 0.20]]

# Update with your Facebook Ad Account ID and Access Token
adaccount_id = ''
access_token = ''

for ratio in ratios:
    for audience_id in audience_ids:
        for country in countries:
            time.sleep(0.5)
            if ratio[0] != ratio[1]:
                data_dump = {
                    'subtype': 'LOOKALIKE',
                    'access_token': access_token,
                    'origin_audience_id': audience_id,
                    'lookalike_spec': json.dumps({
                        'starting_ratio': ratio[0],
                        'ratio': ratio[1],
                        'country': country
                    })
                }
            else:
                data_dump = {
                    'subtype': 'LOOKALIKE',
                    'access_token': access_token,
                    'origin_audience_id': audience_id,
                    'lookalike_spec': json.dumps({
                        'ratio': ratio[0],
                        'country': country
                    })
                }

            r = requests.post('https://graph.facebook.com/v4.0/act_' + adaccount_id + '/customaudiences', data=data_dump)
            result = r.json()
            if 'id' in result:
                print('Adset ID: ' + adset_id + ', Country: ' + country + ', Ratio: ' + str(ratio[0]) + ':' + str(ratio[1]) + ', ' + ' Audience ID: ' + result['id'])
            else:
                print('Adset ID: ' + adset_id + ', Country: ' + country + ', Error: ' + result['error']['message'])