要检查是否存在局部变量:
if 'myVar' in locals(): # myVar exists.
要检查是否存在全局变量:
if 'myVar' in globals(): # myVar exists.
要检查对象是否具有属性:
if hasattr(obj, 'attr_name'): # obj.attr_name exists.

要检查是否存在局部变量:
if 'myVar' in locals(): # myVar exists.
要检查是否存在全局变量:
if 'myVar' in globals(): # myVar exists.
要检查对象是否具有属性:
if hasattr(obj, 'attr_name'): # obj.attr_name exists.