code: def test_inducing_points_inducing_variable_len(
      N: int, D: int
  ) -> None:
      Z = np.random.randn(N, D)
      inducing_variable = InducingPoints(Z)
      assert inducing_variable.num_inducing == N
  
file_path: GPflow/tests/gpflow/covariances/test_base_covariances.py
imports: import numpy
  import pytest
  from numpy.testing import assert_allclose
  import gpflow
  from gpflow.config import default_jitter
  from gpflow.covariances import Kuf, Kuu
  from gpflow.inducing_variables import InducingPatches, InducingPoints, InducingVariables, Multiscale
  from gpflow.kernels import Kernel
label_desc: Use image node_id 1 for calling a global function with example usage: test_inducing_points_inducing_variable_len(N, D) without return types