code: def test_expand_log():
      t = Symbol("t", positive=True)
      # after first expansion, -2*log(2) + log(4); then 0 after second
      assert expand(log(t**2) - log(t**2 / 4) - 2 * log(2)) == 0
      assert expand_log(log(7 * 6) / log(6)) == 1 + log(7) / log(6)
      b = factorial(10)
      assert expand_log(log(7 * b**4) / log(b)) == 4 + log(7) / log(b)
  
imports: from sympy.core.expr import unchanged
  from sympy.core.mul import Mul
  from sympy.core.numbers import I, Rational, pi
  from sympy.core.power import Pow
  from sympy.core.singleton import S
  from sympy.core.symbol import Symbol
  from sympy.functions.combinatorial.factorials import factorial
  from sympy.functions.elementary.exponential import exp, log
  from sympy.functions.elementary.miscellaneous import sqrt
  from sympy.functions.elementary.trigonometric import cos, sin
  from sympy.series.order import O
  from sympy.simplify.radsimp import expand_numer
  from sympy.core.function import expand, expand_multinomial, expand_power_base, expand_log
  from sympy.testing.pytest import raises
  from sympy.core.random import verify_numerically
  from sympy.abc import x, y, z
label_desc: Use image node_id 15 for calling a global function with example usage: test_expand_log() without return types