Class code problem from CS Dojo YouTube

[Dixon]

class Robot:
def introduce_self(self)
print("My name is " + self.name)

r1 = Robot()
r1.name = "Tom"
r1.color = "red"
r1.weight = 30

r2 = Robot()
r2.name = "Jerry"
r2.color = "blue"
r2.weight = 40

r1.introduce_self()
r2.introduce_self()

With the above code, copied from the YouTube channel of CS Dojo, I get a traceback
"name 'r1' is not defined.