code: def _find_custom_op(qualname, also_check_torch_library=False):
      if qualname in global_registry:
          return global_registry[qualname]
      if not also_check_torch_library:
          raise RuntimeError(
              f'Could not find custom op "{qualname}". Did you register it via '
              f"the torch._custom_ops API?"
          )
      overload = get_op(qualname)
      result = custom_op_from_existing(overload)
      return result
  
imports: import dataclasses
  import functools
  import inspect
  import sys
  import typing
  import weakref
  from torchgen.model import FunctionSchema, OperatorName, SchemaKind, BaseType, ListType, BaseTy
  import torch
  import torch._C
  import torch.library
  from torch._library.abstract_impl import AbstractImplCtx
  from torch.library import get_ctx
  from .autograd import autograd_kernel_indirection, construct_autograd_kernel
label_desc: Use image node_id 17 for calling a global function with example usage: _find_custom_op(qualname, also_check_torch_library) and returns: result, global_registry