code: def _normalize_slice(s: slice, dim_size: int) -> slice:
      start = s.start
      if start is None:
          start = 0
      elif start < 0:
          start = dim_size + start
      stop = s.stop
      if stop is None:
          stop = dim_size
      elif stop < 0:
          stop = dim_size + stop
      step = s.step
      if step is None:
          step = 1
      return slice(start, stop, step)
  
imports: import torch
  from linear_operator import LinearOperator, to_linear_operator
  from linear_operator.operators import BlockDiagLinearOperator, BlockInterleavedLinearOperator, CatLinearOperator, DiagLinearOperator
  from .multivariate_normal import MultivariateNormal
label_desc: Use image node_id 2 for calling a global function with example usage: _normalize_slice(s, dim_size) and returns: slice