code: def _get_bias_var(pattern):
      if pattern.add_or_sub.op_type == "sub":
          bias_var = pattern.add_or_sub.y
      else:
          bias_var = (
              pattern.add_or_sub.x
              if pattern.add_or_sub.x.val is not None
              else pattern.add_or_sub.y
          )
  
      return bias_var
  
file_path: coremltools/coremltools/converters/mil/experimental/passes/generic_conv_bias_fusion.py
imports: import os
  import numpy
  from coremltools import _logger
  from coremltools.converters.mil import Builder
  from coremltools.converters.mil.experimental.passes.generic_pass_infrastructure import register_generic_pass
  from coremltools.converters.mil.mil import types
label_desc: Use image node_id 7 for calling a global function with example usage: _get_bias_var(pattern) and returns: bias_var