code: def test_log2_opt():
      x = Symbol("x")
      expr1 = 7 * log(3 * x + 5) / (log(2))
      opt1 = optimize(expr1, [log2_opt])
      assert opt1 == 7 * log2(3 * x + 5)
      assert opt1.rewrite(log) == expr1
  
      expr2 = 3 * log(5 * x + 7) / (13 * log(2))
      opt2 = optimize(expr2, [log2_opt])
      assert opt2 == 3 * log2(5 * x + 7) / 13
      assert opt2.rewrite(log) == expr2
  
      expr3 = log(x) / log(2)
      opt3 = optimize(expr3, [log2_opt])
      assert opt3 == log2(x)
      assert opt3.rewrite(log) == expr3
  
      expr4 = log(x) / log(2) + log(x + 1)
      opt4 = optimize(expr4, [log2_opt])
      assert opt4 == log2(x) + log(2) * log2(x + 1)
      assert opt4.rewrite(log) == expr4
  
      expr5 = log(17)
      opt5 = optimize(expr5, [log2_opt])
      assert opt5 == expr5
  
      expr6 = log(x + 3) / log(2)
      opt6 = optimize(expr6, [log2_opt])
      assert str(opt6) == "log2(x + 3)"
      assert opt6.rewrite(log) == expr6
  
imports: import tempfile
  from sympy.core.numbers import pi, Rational
  from sympy.core.power import Pow
  from sympy.core.singleton import S
  from sympy.core.symbol import Symbol
  from sympy.functions.elementary.complexes import Abs
  from sympy.functions.elementary.exponential import exp, log
  from sympy.functions.elementary.trigonometric import cos, sin, sinc
  from sympy.matrices.expressions.matexpr import MatrixSymbol
  from sympy.assumptions import assuming, Q
  from sympy.external import import_module
  from sympy.printing.codeprinter import ccode
  from sympy.codegen.matrix_nodes import MatrixSolve
  from sympy.codegen.cfunctions import log2, exp2, expm1, log1p
  from sympy.codegen.numpy_nodes import logaddexp, logaddexp2
  from sympy.codegen.scipy_nodes import cosm1, powm1
  from sympy.codegen.rewriting import optimize, cosm1_opt, log2_opt, exp2_opt, expm1_opt, log1p_opt, powm1_opt, optims_c99, create_expand_pow_optimization, matinv_opt, logaddexp_opt, logaddexp2_opt, optims_numpy, optims_scipy, sinc_opts, FuncMinusOneOptim
  from sympy.testing.pytest import XFAIL, skip
  from sympy.utilities import lambdify
  from sympy.utilities._compilation import compile_link_import_strings, has_c
  from sympy.utilities._compilation.util import may_xfail
label_desc: Use image node_id 1 for calling a global function with example usage: test_log2_opt() without return types