old_contents: ##Exemplo retirado do site http://code.tutsplus.com/tutorials/beginning-test-driven-development-in-python--net-30137
  
  class Calculator(object):
      def add(self, x, y):
  
          number_types = (int, float, complex)
  
          if isinstance(x, number_types) and isinstance(y, number_types):
              return x + y
          else:
              raise ValueError
  
new_contents: ##Exemplo retirado do site http://code.tutsplus.com/tutorials/beginning-test-driven-development-in-python--net-30137
  
  class Calculator______(object):
      def add(self, x, y):
  
          number_types = (int, float, complex)
  //sasasaslfdjdhfjlhlsjkhflskdjhflkshlfkhsfhskfhsd
  #@323232323233232
  
  lfjdslfsfhjshfjkhskfjhjshfkljshrifjsd
          if _________isinstance(x, number_types) and _____isinstance(y, number_types):
              return x + y
          else:
              raise ValueError
  
subject: Update calculator.py