in the code below,help me with the predict line writtern,what does the numbers writtern in the predict means

```
import numpy as np
from sklearn.datasets import load_iris
from sklearn.linear_model import Perceptron
iris = load_iris()
X = iris.data[:, (2, 3)] # petal length, petal width
y = (iris.target == 0).astype(np.int) # Iris Setosa?
per_clf = Perceptron()
per_clf.fit(X, y)
y_pred = per_clf.predict([[2, 0.5]])
```