code: def __init__(
      self, num_features: int, eps: float = 1e-5, affine: bool = True
  ):
      self.num_features, self.eps = num_features, eps
      self.weight: Optional[Tensor] = (
          Tensor.ones(num_features) if affine else None
      )
      self.bias: Optional[Tensor] = (
          Tensor.zeros(num_features) if affine else None
      )
  
imports: import math
  from typing import Optional, Union, Tuple, cast
  from tinygrad.tensor import Tensor
  from tinygrad.helpers import prod
  from tinygrad.nn import optim, state
label_desc: Use image node_id 1 to create a new InstanceNorm object  with example: obj = InstanceNorm(num_features, eps, affine)