code: def lag(
      s: "Stream[T]", lag: int = 1, dtype: str = None
  ) -> "Stream[T]":
      """Creates a lag stream.
  
      Parameters
      ----------
      s : `Stream[T]`
          A generic stream.
      lag : int, default 1
          The number of steps to lag behind by
      dtype : str, optional
          The data type of the stream
  
      Returns
      -------
      `Stream[T]`
          A lag stream of `s`.
      """
      if dtype is None:
          dtype = s.dtype
      return Lag(lag, dtype=dtype)(s)
  
imports: from typing import Callable
  from tensortrade.feed.core.base import Stream, T
  from tensortrade.feed.core.operators import Apply, Lag, Freeze, Accumulator, Copy, TypeVar
label_desc: Use image node_id 2 for calling a global function with example usage: lag(s, lag, dtype) and returns: Lag