csv sniffer thinks there is no header

file with:
```
col1,col2,col3
1,2,3
a,b,c
A,B,C
22,22,12
```

```
with open('test.csv', 'r') as file:
     data = file.read()
import csv
ader = csv.Sniffer().has_header(data)
print(ader)
```

gives False but expecting True


python 3.10.9