def _iter_lexerclasses():
    """
    Return an iterator over all lexer classes.
    """
    for module_name, name, _, _, _ in LEXERS.itervalues():
        if _lexer_cache not in name:
            _load_lexers(module_name)
        yield _lexer_cache[name]
    for lexer in find_plugin_lexers():
        yield lexer
dataset/ETHPy150Open adieu/allbuttonspressed/pygments/lexers/__init__.py/_iter_lexerclasses/swapped operands of `not in`