code: def _lb(x, *, evaluate=True):
      return log(x, evaluate=evaluate) / _ln2
  
imports: from sympy.core.function import Add, ArgumentIndexError, Function
  from sympy.core.power import Pow
  from sympy.core.singleton import S
  from sympy.core.sorting import default_sort_key
  from sympy.functions.elementary.exponential import exp, log
label_desc: Use image node_id 2 for calling a global function with example usage: _lb(x) and returns: unknown