def __init__(self, ds, num=1, name=None, max_depth=3, max_list=3):
        """
        Args:
            ds (DataFlow): input DataFlow.
            num (int): number of dataflow points to print.
            name (str, optional): name to identify this DataFlow.
            max_depth (int, optional): stop output when too deep recursion in sub elements
            max_list (int, optional): stop output when too many sub elements
        """
        super(PrintData, self).__init__(ds)
        self.num = num
        self.name = name
        self.cnt = 0
        self.max_depth = max_depth
        self.max_list = max_list

        Args:
            ds (DataFlow): input DataFlow.
            num (int): number of dataflow points to print.
            name (str, optional): name to identify this DataFlow.
            max_depth (int, optional): stop output when too deep recursion in sub elements
            max_list (int, optional): stop output when too many sub elements
        
tensorpack/dataflow/common.py