Invocation not found on a var[].func()

```
import numpy as np
import pandas as pd
import tensorflow as tf
from tensorflow import keras
train = pd.read_csv('/kaggle/input/titanic/train.csv')
train['Sec_Name'] = train['Name'].astype(str).str.split().str[1]
```

No accesses or invocations are created on line : `train['Name'].astype(str).str.split().str[1]`