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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def populate(self, source=DEFAULT_SEGMENT_SERVER, segments=None, pad=True, **kwargs):
 """Query the segment database for this flag's active segments. This method assumes all of the metadata for each flag have been filled. Minimally, the following attributes must be filled .. autosummary:: ~DataQualityFlag.name ~DataQualityFlag.known Segments will be fetched from the database, with any :attr:`~DataQualityFlag.padding` added on-the-fly. This `DataQualityFlag` will be modified in-place. Parameters source : `str` source of segments for this flag. This must be either a URL for a segment database or a path to a file on disk. segments : `SegmentList`, optional a list of segments during which to query, if not given, existing known segments for this flag will be used. pad : `bool`, optional, default: `True` apply the `~DataQualityFlag.padding` associated with this flag, default: `True`. **kwargs any other keyword arguments to be passed to :meth:`DataQualityFlag.query` or :meth:`DataQualityFlag.read`. Returns ------- self : `DataQualityFlag` a reference to this flag """

        tmp = DataQualityDict()
        tmp[self.name] = self
        tmp.populate(source=source, segments=segments, pad=pad, **kwargs)
        return tmp[self.name]