def __init__(self, max_idle_time=60):
"""
Create a new instance.
max_idle_time - max idle time in seconds
"""
if self.__class__._instance:
msg = "FileHandleManager is a singleton. Call get_instance()"
raise ValueError(msg)
self.max_idle_time = max_idle_time
self.cache = OrderedDict()
self.__class__._instance = self
