class_docstr: Fold pow(x, 2) --> sqrt(x) into identity(x)
  
  Given:
      %1 = pow(x=%0, y=2)
      %2 = sqrt(x=%1)
      ...
      %1 = sqrt(x=%0)
      %2 = pow(x=%1, y=2)
      ...
  
  Result:
      %3 = identity(%0)
      ...
code: def apply(self, prog):
      for f in prog.functions.values():
          block_changed = True
          while block_changed:
              block_changed = _fuse_pow2_sqrt(f)
  
file_path: coremltools/coremltools/converters/mil/backend/mil/passes/fuse_pow2_sqrt.py
imports: from coremltools.converters.mil.mil import Builder
  from coremltools.converters.mil.mil.passes.graph_pass import AbstractGraphPass
  from coremltools.converters.mil.mil.passes.helper import block_context_manager
  from coremltools.converters.mil.mil.passes.pass_registry import register_pass
label_desc: Use image node_id 1 for calling the fuse_pow2_sqrt obj's underlying member method code with example usage: obj.apply(prog) without return types