def find_lexer_class(name):
    """
    Lookup a lexer class by name. Return None if not found.
    """
    if name in _lexer_cache:
        return _lexer_cache[name]
    # lookup builtin lexers
    for module_name, lname, aliases, _, _ in LEXERS.itervalues():
        if name == lname:
            _load_lexers(module_name)
            return _lexer_cache[name]
    # continue with lexers from setuptools entrypoints
    for cls in find_plugin_lexers():
        if cls.name == name:
            return cls
dataset/ETHPy150Open adieu/allbuttonspressed/pygments/lexers/__init__.py/find_lexer_class/original