Need help to understand the following code

Question

Here, we have created a convolutional neural network and switched off the top layer and then we are creating top layer. I add layers with model.add but here I find it a little confusing.

from tensorflow.keras.layers import AveragePooling2D
from tensorflow.keras.layers import Dropout
from tensorflow.keras.layers import Flatten
from tensorflow.keras.layers import Dense  

headModel = base_model.output
headModel = AveragePooling2D(pool_size=(7, 7))(headModel)
headModel = Flatten(name="flatten")(headModel)
headModel = Dense(128, activation="relu")(headModel)
headModel = Dropout(0.5)(headModel)
headModel = Dense(2, activation="softmax")(headModel)  

Can someone please explain to me this syntax.