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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 _get_3000_galaxies_needing_metadata( self):
 """ get 3000 galaxies needing metadata **Return:** - ``len(self.theseIds)`` -- the number of NED IDs returned .. todo :: - update key arguments values and definitions with defaults - update return values and definitions - update usage examples and text - update docstring text - check sublime snippet exists - clip any useful text to docs mindmap - regenerate the docs and check redendering of this docstring """

        self.log.debug(
            'starting the ``_get_3000_galaxies_needing_metadata`` method')

        tableName = self.dbTableName

        # SELECT THE DATA FROM NED TABLE
        self.theseIds = {}
        sqlQuery = u"""
            select primaryId, primary_ned_id from %(tableName)s where master_row = 1 and in_ned is null limit 3000;
        """ % locals()
        rows = readquery(
            log=self.log,
            sqlQuery=sqlQuery,
            dbConn=self.cataloguesDbConn,
            quiet=False
        )
        for row in rows:
            self.theseIds[row["primary_ned_id"]] = row["primaryId"]

        self.log.debug(
            'completed the ``_get_3000_galaxies_needing_metadata`` method')

        return len(self.theseIds)