class_docstr: Fold ``add``/``sub`` into ``bias`` of ``conv`` and ``conv_transpose``.
  That is, convert ``conv + add/sub`` to ``conv``, when ``add``/``sub`` is adding a constant.
  
  Two patterns are supported:
  
  .. code-block::
  
      Pattern 1:
      Given:
          %2 = conv(%1)
          ...
          %3 = add(%2, constant) # where constant has shape (1,C,1)/(C,1) for 1d conv, (1,C,1,1)/(C,1,1) for 2d conv etc
          ...
  
      Result:
          %3 = conv(%1)
          ...
  
  
      Pattern 2:
      Given:
          %2 = conv(%1)
          %3 = transpose(%2)
          ...
          %4 = add(%3, constant) # where constant has a broacasable shape
          ...
  
      Result:
          %2 = conv(%1)
          %4 = transpose(%2)
          ...
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code: def _match_pattern(self, op):
      if op.op_type == "conv" or op.op_type == "conv_transpose":
          # abort fusion if op output is also a block output
          if op.outputs[0] in op.enclosing_block.outputs:
              return None
          # find add
          child_ops = op.outputs[0].child_ops
          if len(child_ops) == 1:
              add_op_candidate = list(child_ops)[0]
              if add_op_candidate.op_type in self.child_op_types:
                  return add_op_candidate
      return None
  
imports: import copy
  import numpy
  from coremltools import _logger
  from coremltools.converters.mil.mil import Block
  from coremltools.converters.mil.mil import Builder
  from coremltools.converters.mil.mil import Operation, types
  from coremltools.converters.mil.mil.passes.graph_pass import AbstractGraphPass
  from coremltools.converters.mil.mil.passes.helper import _check_child_op_type, _check_no_output_connection, block_context_manager
  from coremltools.converters.mil.mil.passes.pass_registry import register_pass
  from coremltools.converters.mil.mil.types.symbolic import any_symbolic
label_desc: Use image node_id 2 for calling the fuse_conv_bias obj's underlying member method code with example usage: obj._match_pattern(op) and returns: None, None, add_op_candidate