code: def deprecated(alternative=None):
      
  
      def real_decorator(func):
          @functools.wraps(func)
          def new_func(*args, **kwargs):
              msg = "Call to deprecated function {0}.".format(func.__name__)
              if alternative:
                  msg += " Use {0} instead".format(alternative)
              warnings.warn_explicit(
                  msg,
                  category=DeprecationWarning,
                  filename=compat.get_function_code(func).co_filename,
                  lineno=compat.get_function_code(func).co_firstlineno + 1,
              )
              return func(*args, **kwargs)
  
          return new_func
  
      return real_decorator
docs: This is a decorator which can be used to mark functions
      as deprecated. It will result in a warning being emitted
      when the function is used.