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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_block_from_consensus( self, consensus_hash ):
 """ Get the block number with the given consensus hash. Return None if there is no such block. """

        query = 'SELECT block_id FROM snapshots WHERE consensus_hash = ?;'
        args = (consensus_hash,)

        con = self.db_open(self.impl, self.working_dir)
        rows = self.db_query_execute(con, query, args, verbose=False)
        res = None

        for r in rows:
            res = r['block_id']

        con.close()
        return res