code: def returns(schema):
      
      validate = parse(schema).validate
  
      @decorator
      def validating(func, *args, **kwargs):
          ret = func(*args, **kwargs)
          validate(ret, adapt=False)
          return ret
      return validating
docs: Create a decorator for validating function return value.
  
      Example::
          @accepts(a=int, b=int)
          @returns(int)
          def f(a, b):
              return a + b
  
      :param schema: The schema for adapting a given parameter.