from math import pi as pi


class Kreis_getattr:
  def __init__(self, radius):
    self.radius = radius
    self.operators ={
        'durchmesser': lambda x: self.radius * 2,
        'umfang': lambda x: self.durchmesser * pi,
        'flaeche': lambda x: self.radius**2 *pi
    }

  def __getattr__(self, name):
      if name not in self.operators:
        raise TypeError(f'unbekannte Operation {name}')

      return self.operators[name](0)