TypeError: unsupported operand type(s) for +: 'Period' and 'Period'

I have transformed the below dict into the Dataframe below,

xxx = {'Jack': ['EU','950','13000','16','20 km',[0]],
'John': ['EU','440','550','12','50m',[0]],
'Tim': ['US','750','2200','12','25 m',[0]],
'Tom': ['US','850','6000','16','20 km',['2022-04-10','2022-04-11','2022-04-12','2022-06-13','2022-06-14','2022-06-15','2022-07-21','2022-07-22','2022-07-23','2022-07-24','2022-07-25','2022-09-12','2022-09-13','2022-09-16','2022-09-26','2022-09-27']],
'Sarah': ['US','900','11000','33','17 km',['2022-01-01','2022-01-02','2022-03-26','2022-03-27','2022-03-28','2022-04-10','2022-04-11','2022-04-12','2022-04-13','2022-04-14','2022-06-03','2022-06-04','2022-06-05','2022-06-11','2022-06-19']]}

xxx = pd.DataFrame.from_dict(xxx, 'index').explode(5).reset_index()
xxx[5] = pd.to_datetime(xxx[5], format='%Y-%m-%d').dt.to_period('M')
xxx = xxx.groupby(['index',0,1,2,3,4,5]).size().unstack(fill_value=0) 
del xxx['1970-01']
xxx.reset_index(inplace=True)
print(xxx)

5  index   0    1      2   3      4  2022-01  2022-03  2022-04  2022-06  \
0   Jack  EU  950  13000  16  20 km        0        0        0        0   
1   John  EU  440    550  12    50m        0        0        0        0   
2  Sarah  US  900  11000  33  17 km        2        3        5        5   
3    Tim  US  750   2200  12   25 m        0        0        0        0   
4    Tom  US  850   6000  16  20 km        0        0        3        3   

5  2022-07  2022-09  
0        0        0  
1        0        0  
2        0        0  
3        0        0  
4        5        5 

I would like to insert a Sum column that will sum the counts for the date columns

My code:

    xxx['sum'] = sum(xxx.iloc[:,-6:])
TypeError: unsupported operand type(s) for +: 'Period' and 'Period'

1. Please, help to insert the Sum column that will sum the counts of the last 6 columns
2. Why does my index column have header 5?

>Solution :

Use sum method of dataframe rather than sum function:

xxx['sum'] = xxx.iloc[:,-6:].sum(axis=1)
print(xxx.iloc[:,-7:])

# Output
5  2022-01  2022-03  2022-04  2022-06  2022-07  2022-09  sum
0        0        0        0        0        0        0    0
1        0        0        0        0        0        0    0
2        2        3        5        5        0        0   15
3        0        0        0        0        0        0    0
4        0        0        3        3        5        5   16