如何查看Python内置方法的源代码？

Question

如何查看getattr源代码？

class A(object):
    def __init__(self):
        name = "a"

if __name__ == '__main__':

    a = A()
    print(getattr(a, 'name', 'nihao'))

在我的PyCharm中，我 Command + 单击内置方法 getattr ，然后跳到该文件/Users/xxx/Library/Caches/PyCharm2017.2/python_stubs/776880377/builtins.py：

但是没有实现它：

def getattr(object, name, default=None): # known special case of getattr
    """
    getattr(object, name[, default]) -> value

    Get a named attribute from an object; getattr(x, 'y') is equivalent to x.y.
    When a default argument is given, it is returned when the attribute doesn't
    exist; without it, an exception is raised in that case.
    """
    pass 

如何查看内置方法的源代码？