code: def graph():
      graph = StructureModel()
      edges = [(n, n + 1, 1) for n in range(5)]
      graph.add_weighted_edges_from(edges)
      return graph
  
imports: import operator
  from typing import Hashable, Tuple, Union
  import networkx
  import numpy
  import pandas
  import pytest
  from networkx.algorithms.dag import is_directed_acyclic_graph
  from sklearn.gaussian_process.kernels import RBF
  from causalnex.structure.data_generators.core import _sample_binary_from_latent, _sample_count_from_latent, _sample_poisson, generate_structure, nonlinear_sem_generator, sem_generator
  from causalnex.structure.structuremodel import StructureModel
label_desc: Use image node_id 1 for calling a global function with example usage: graph() and returns: graph