how to protect variables in python code example

Example 1: python protected attributes

class example:
  def __init__(self):
    self._variable1='protected variale' 
    self.__variable2='private variable'
    self.variable3='public variable'

Example 2: python protected method

class example:
  def __init__(self):
    self._method1() #protected
    self.__method3() #private
    self.method3() #public