old_contents: from ast import NodeVisitor
  
  
  class YieldSearch(NodeVisitor):
  
      def visit_Yield(self, node):
          self.has_yield = True
  
new_contents: from ast import NodeVisitor
  
  
  class YieldSearch(NodeVisitor):
  
      def visit_Yield(self, node):
          self.has_yield = True
  
      def visit_FunctionDef(self, node):
          pass  # do not visit nest function definition to determine
                # if a function has a yield or not...
  
subject: fix nested generator definition