old_contents: """onnx optimizer
  
  """
  from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  
  import onnx.onnx_cpp2py_export.optimizer as C
  
  optimize = C.optimize
  
new_contents: """onnx optimizer
  
  This enables users to optimize their models.
  """
  from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  
  import onnx.onnx_cpp2py_export.optimizer as C
  
  """Apply the optimization on the serialized ModelProto.
  
  Arguments:
      input (string): serialized ModelProto
      names (list of string): list of optimization names
  
  Supported pass names:
      -- eliminate_nop_transpose
      -- fuse_consecutive_transposes
      -- fuse_transpose_into_gemm
  """
  optimize = C.optimize
  
subject: Add docs for optimizer