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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_select_commands(self, source, tables):
 """ Create select queries for all of the tables from a source database. :param source: Source database name :param tables: Iterable of table names :return: Dictionary of table keys, command values """

        # Create dictionary of select queries
        row_queries = {tbl: self.select_all(tbl, execute=False) for tbl in
                       tqdm(tables, total=len(tables), desc='Getting {0} select queries'.format(source))}

        # Convert command strings into lists of commands
        for tbl, command in row_queries.items():
            if isinstance(command, str):
                row_queries[tbl] = [command]

        # Pack commands into list of tuples
        return [(tbl, cmd) for tbl, cmds in row_queries.items() for cmd in cmds]