How to fetch count of total leads from Facebook ads using python SDK?

Question

I want to fetch the count of all the leads from Facebook ads using python SDK, Does anyone knows which field or method needs to be used to fetch the count?

        fields = [
                        
                        AdsInsights.Field.account_id,                
                        AdsInsights.Field.account_name
                  ]
    params = {
                    'time_range': {
                        'since':  "2022-05-01",
                        'until': today_date
                    },
                    'breakdowns': ['region'],
                    'level': 'ad',
                    'time_increment': 1
                }
   async_job = account.get_insights_async(fields=fields, params=params)

I have tried this python code but am not able to fetch the count of total leads, Please help