>>> cache = Cache(log_level=logging.WARNING)
        >>> cache.set_evict_number(10)
        >>> cache.evict_number
        10
        >>> cache.set_evict_number('haha')
        >>> cache.evict_number
        10

def set_evict_number(self, new_evict_number, only_read=False):
        """
        >>> cache = Cache(log_level=logging.WARNING)
        >>> cache.set_evict_number(10)
        >>> cache.evict_number
        10
        >>> cache.set_evict_number('haha')
        >>> cache.evict_number
        10
        """
        if not isinstance(new_evict_number, int) or new_evict_number <= 0:
            self.logger.warning(
                'Parameter new_evict_number %s must be greater than 0 and is an integer' % new_evict_number)
            return
        self.evict_number = new_evict_number