what does x reprsent in this code ?

[astral_travel]

another quiz,
in the following code:

class MyNumbers:
  def __iter__(self):
    self.a = 1
    return self

  def __next__(self):
    if self.a <= 20:
      x = self.a
      self.a += 1
      return x
    else:
      raise StopIteration

myclass = MyNumbers()
myiter = iter(myclass)

for x in myiter:
  print(x)

i see that in line 14 - myclass = Mynumbers() - as i understand it - myclass is a new variable ? which is assigned the value of the class MyNumbers ?
but then how is it that the class is being wrote with () - (that's a function feature, isn't it ?)