sklearn imputer ValueError: Input contains NaN, infinity or a value too large for dtype('float64'). code example

Example: ValueError: Input contains NaN, infinity or a value too large for dtype('float32').

# Loads your dataset, drops labels and response variable as usual...
df = pd.read_csv('train_test.csv', sep=',')
X = df.drop(["label_1","label_2","response_var"], axis=1)
y = df['response_var']

# this will print TRUE or FALSE for positions containing or not NaN
# values in your dataset

print(np.isnan(X))