code: def _check_nodes_references_correct(graph):
      for node in graph.nodes:
          if node.nodes_from:
              for parent_node in node.nodes_from:
                  if parent_node not in graph.nodes:
                      return False
      return True
  
imports: from copy import deepcopy
  from random import choice
  import numpy
  import pytest
  from golem.core.dag.graph_node import GraphNode
  from golem.core.dag.graph_verifier import GraphVerifier
  from golem.core.dag.verification_rules import DEFAULT_DAG_RULES
  from golem.core.optimisers.graph import OptNode
  from fedot.core.operations.operation import Operation
  from fedot.core.pipelines.adapters import PipelineAdapter
  from fedot.core.pipelines.node import PipelineNode
  from fedot.core.pipelines.pipeline import Pipeline
  from fedot.core.pipelines.pipeline_builder import PipelineBuilder
  from test.unit.dag.test_graph_utils import find_first
  from test.unit.tasks.test_regression import get_synthetic_regression_data
label_desc: Use image node_id 11 for calling a global function with example usage: _check_nodes_references_correct(graph) and returns: True, False