code: def test_mul():
      f = F.Factor("t", [2, 3])
      f2 = F.Factor("t", [2, 3, 4])
      t2 = f["t_2"]
      x = F.Term("x")
      assert t2 == t2 * t2
      assert f == f * f
      assert f != f2
      assert set((t2 * x).atoms()) == {t2, x}
  
imports: from warnings import catch_warnings, simplefilter
  import numpy
  import pytest
  import sympy
  from numpy.core.records import fromrecords
  from numpy.testing import assert_almost_equal, assert_array_equal
  from sympy.utilities.lambdify import implemented_function
  from nipy.utils import VisibleDeprecationWarning
  from ..None import formulae
  from ..formulae import Term, terms
label_desc: Use image node_id 9 for calling a global function with example usage: test_mul() without return types