code: def _ignore_variable(filename, varname):
      
      return (
          varname in IGNORED_VARIABLE_NAMES or
          (varname.startswith('_') and not varname.startswith('__')) or
          _is_special_name(varname))
docs: Ignore _ (Python idiom), _x (pylint convention) and
      __x__ (special variable or method), but not __x.