kinematic on_body_enter

Hey, guys, I really don't get how to use a body_enter function, please explain.
I got two nodes Player and Enemy and they both are KinematicBodies2D.
Enemy node has got an Area2D node in it with script like this:

extends Area2D

func _ready():
    connect("body_enter", self, "_on_enemy_body_enter")


func _on_enemy_body_enter(body):
    print("Collision")
    if (body.get_name == "Player"):
        print("Ouch!")