code: def _safe_processing(nsafefn, source, _globals=None, _locals=None):
      
  
      if _globals is None:
          _globals = SAFE_BUILTINS
  
      else:
          _globals.update(SAFE_BUILTINS)
  
      return nsafefn(source, _globals, _locals)
docs: Do a safe processing of input fn in using SAFE_BUILTINS.
  
      :param fn: function to call with input parameters.
      :param source: source object to process with fn.
      :param dict _globals: global objects by name.
      :param dict _locals: local objects by name.
      :return: fn processing result