old_contents: 
  "doc string"
  
  def x(a, b):
      pass
  
  class X:
      "doc"
      def __init__(self):
          self.y = 0
      def z(self):
      "this should not have any warnings"
          x(self.y, { 'a': 'b' })
  
  
new_contents: 
  "doc string"
  
  def x(a, b):
      pass
  
  class X:
      "doc"
      def __init__(self):
          self.y = 0
      def z(self):
          "this should not have any warnings"
          x(self.y, { 'a': 'b' })
  
  
subject: fix doc string, put at right indentation