import datetime
t_= '2021-02-04T10:54:00,123'
s_time = datetime.datetime.strptime(t_,'%Y-%m-%dT%H:%M:%S,%f')
print(s_time.timestamp())
1612407240.123
import datetime
t_= '2021-02-04T10:54:00,123'
s_time = datetime.datetime.strptime(t_,'%Y-%m-%dT%H:%M:%S,%f')
print(s_time.timestamp())
1612407240.123