Failed to download data from facebookAds through its API

Question

I am looking to access the Facebook ADS data to automate the download of the data and its visualization, this in order to build campaign monitoring reports and KPIs.

My main option was to use the Facebook Graph API and from Python use the token to access the data, I already have a script that shows me the accounts and campaigns but when I review the metrics and campaigns it does not extract data, my intention is to download and save the data to a CSV but it remains empty.

I don't know what the error is, could you help me?

    Import facebook_business

from facebook_business.adobjects.adaccount import AdAccount
from facebook_business.adobjects.campaign import Campaign
from facebook_business.adobjects.adsinsights import AdsInsights
from facebook_business.adobjects.adaccountuser import AdAccountUser as AdUser
from facebook_business.api import FacebookAdsApi

access_token = 'xxxxxxx'
app_secret = 'xxxxxxx'
app_id = 'xxxxxx'
FacebookAdsApi.init(access_token=access_token)

me = AdUser(fbid='me')
my_accounts = list(me.get_ad_accounts())

for a in my_accounts: # each account
  fields = ['name','objective','start_time','stop_time','effective_status']
  params = {'effective_status': ['ACTIVE', 'PAUSED']}
  camp = AdAccount(a['id']).get_campaigns(fields=fields,params=par
fields=[AdsInsights.Field.date_start,AdsInsights.Field.date_stop, AdsInsights.Field.reach,
        AdsInsights.Field.impressions, AdsInsights.Field.spend, AdsInsights.Field.frequency,
        AdsInsights.Field.clicks, AdsInsights.Field.unique_clicks, AdsInsights.Field.cpc,
        AdsInsights.Field.cpm, AdsInsights.Field.ctr, AdsInsights.Field.unique_ctr, 
        AdsInsights.Field.cost_per_unique_click, AdsInsights.Field.website_purchase_roas,
        AdsInsights.Field.account_name]  
params = {'date_preset_enum': 'lifetime','time_increment':1}

filename = 'C:/Users/mlozanonon/O/BI/'+a['account_id']+'.csv' 
separator = ","
# Header
header = "name,campaign_id,"
for f in fields:
  header+=str(f)
  header+=separator
with open(filename, 'w') as output:
  output.write(header)
  output.write("\n")
for c in camp: # Each campaign
  insigths = c.get_insights(fields=fields,params=params)
  for i in insigths: # Each campaign element
    data = c['name']
    data += separator
    data += c['id']
    data += separator
    for f in fields:
      if len(i) > 0: # There is data
        if f in i: # Field is present
          data += str(i[f])
      data += separator
    output.write(data)