code: def LayerNorm(nI: Optional[int] = None) -> Model[InT, InT]:
      return Model(
          "layernorm",
          forward,
          init=init,
          dims={"nI": nI, "nO": nI},
          params={"G": None, "b": None},
      )
  
file_path: thinc/thinc/layers/layernorm.py
imports: from typing import Callable, Optional, Tuple, cast
  from ..backends import Ops
  from ..config import registry
  from ..model import Model
  from ..types import Floats2d
  from ..util import get_width
label_desc: Use image node_id 1 for calling a global function with example usage: LayerNorm(nI) and returns: Model