def __init__(self):
        """

        :param select_f: A function which takes  source and a row and returns a PartialPartitionName
        :return:
        """

        # The partitions are stored in both the data files and the partitions dicts, because
        # the _datafiles may have multiple copies of the same partition, and they all have to
        # be the same instance.
        self._datafiles = {}  # Partitions associated with table mappers
        self._partitions = {}  # Just the partitions.
        self._headers = {}
        self.headers = None
        self.p_name_index = None

        self.header_mapper, self.body_mapper = None, None

        self._start_time = None
        self._end_time = None
        self._count = 0
        self._source_id = None
def __init__ ( self ) : self . _datafiles = { } self . _partitions = { } self . _headers = { } self . headers = None self . p_name_index = None self . header_mapper , self . body_mapper = None , None self . _start_time = None self . _end_time = None self . _count = 0 self . _source_id = None
:param select_f: A function which takes  source and a row and returns a PartialPartitionName
        :return: