code: def curr_block():
      if len(BLOCK_STACK) == 0:
          raise ValueError(
              "Must call Builder inside an Function" + " or Block"
          )
      return BLOCK_STACK[-1]
  
imports: import copy
  from collections import Counter, OrderedDict
  from typing import Tuple
  from coremltools import _OPSET
  from coremltools import _logger
  from coremltools.converters.mil._deployment_compatibility import AvailableTarget
  from .None import SPACES, types
  from .operation import Operation
  from .types.symbolic import is_symbolic, k_used_symbols
  from .var import ComplexVar, InternalVar, Var
  from .visitors.dot_visitor import DotVisitor
label_desc: Use image node_id 1 for calling a global function with example usage: curr_block() and returns: BLOCK_STACK