I read date from a CSV files

The code is:
data.isnull().sum()

Why all are 0???

listings 0
url 0
guests 0
bedrooms 0
bed 0
bathrooms 0
room_type 0
price 0
host_name 0
reviews 0
stars 10
location 0
latitude 0
longitude 0
dtype: int64
CSV file is