Find Null values in DF

import pandas as pd
df = pd.read_csv('train.csv')
df.isnull().sum().any()
False

If this value is True we need to find the columns that are null

df.isnull().sum()
ID           0
target       0
48df886f9    0
0deb4b6a8    0
34b15f335    0
            ..
71b203550    0
137efaa80    0
fb36b89d9    0
7e293fbaf    0
9fc776466    0
Length: 4993, dtype: int64

No values were null so the 4th cell was not needed