code: def train_data():
      train_x = torch.linspace(0, 1, 260)
      train_y = torch.cos(train_x * (2 * math.pi))
      return train_x, train_y
  
file_path: gpytorch/test/examples/test_decoupled_svgp_regression.py
imports: import math
  import unittest
  from unittest.mock import MagicMock, patch
  import linear_operator
  import torch
  from torch import optim
  import gpytorch
  from gpytorch.likelihoods import GaussianLikelihood
  from gpytorch.models import ApproximateGP
  from gpytorch.test.base_test_case import BaseTestCase
label_desc: Use image node_id 1 for calling a global function with example usage: train_data() and returns: train_x,  train_y