PyLint类错误

Question

在python 2.7上的pylint中我收到以下错误：

common/cdn/edgecast/EdgeCast.py:14: [E0239(inherit-non-class), EdgeCast] Inheriting 'Base', which is not a class.

以下是EdgeCast和Base的相关代码：

EdgeCast.py

from common.cdn import Base


class EdgeCast(Base):
    """
    Class comment
    """
    def __init__(self, account, db_conn=None):
        super(EdgeCast, self).__init__(account, db_conn=db_conn)

Base.py

class Base(object):
    """
    Class comment
    """
    def __init__(self, account, db_conn=None):
        pass

有人能指出让PyLint看到Base不是一个类的原因吗？