code: def test_FreeGroupElm_methods():
      assert (x**0).order() == 1
      assert (y**2).order() is oo
      assert (x**-1 * y).commutator(x) == y**-1 * x**-1 * y * x
      assert len(x**2 * y**-1) == 3
      assert len(x**-1 * y**3 * z) == 5
  
imports: from sympy.combinatorics.free_groups import free_group, FreeGroup
  from sympy.core import Symbol
  from sympy.testing.pytest import raises
  from sympy.core.numbers import oo
label_desc: Use image node_id 10 for calling a global function with example usage: test_FreeGroupElm_methods() without return types