code: def test_FreeGroupElm_syllables():
      w = x**5 * y * x**2 * y**-4 * x
      assert w.number_syllables() == 5
      assert w.exponent_syllable(2) == 2
      assert w.generator_syllable(3) == Symbol("y")
      assert w.sub_syllables(1, 2) == y
      assert w.sub_syllables(3, 3) == F.identity
  
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 18 for calling a global function with example usage: test_FreeGroupElm_syllables() without return types